Olly Alexander bounds down the stairs of his flat to greet me with a hug. It’s a big flat, stretched over two floors, huge windows overlooking a pretty London park. There are books everywhere, in scattered, haphazard piles; he is just about to start Two Serious Ladies by Jane Bowles, a gift from a friend. There’s a Joni Mitchell songbook propped up on his piano, and there are massive houseplants all over the place. He left his old flat, not too far from here, after several lockdowns, because it didn’t have any outdoor space. This one, which has a huge balcony, is rented, so he didn’t buy the furniture, but the plants are his. “I’m a plant gay,” he quips, drily.

Alexander has a puppyish energy. He is lively and charming and clearly very sensitive. On his sofa, he curls his legs underneath him, his trademark red hair (he once told Rihanna she inspired it) tucked under a baseball cap on which is printed Business of Pleasure. He is fun and chatty and acutely self-aware: he was in the audience for the Adele ITV live special recently, among an extraordinary buffet of celebrities, and he serves up good gossip about a couple of them, doing a brief, uncanny impression of Mel B. Boy George was sitting near him, which leads us on to The Real Housewives of Beverly Hills, a reality show that Boy George appears in and that Alexander became obsessed with during lockdown. “I won’t go on and on about The Real Housewives of Beverly Hills, even though I could … ” he says – and then he does.

Fame fascinates Alexander, and it also seems to repel him. Throughout our conversation, he treats it like a puzzle he is trying to solve. Now 31, he has had a fair taste of it, both as a singer and an actor. From the age of 18, he was an actor on the up, appearing in, among other things, Skins, and Peter and Alice in the West End, alongside Dame Judi Dench and Ben Whishaw. When he was 20, he joined the band Years & Years and became a pop star.

Years & Years – of which he is now the only member, more on which shortly – sell out arena tours, win awards, and have topped the album and singles charts. He has done Celebrity Gogglebox with his mum, Vicki. In 2021, he performed with Elton John at the Brits. The weekend after we meet, he performs his new single live on Strictly Come Dancing.

But at the end of 2019, he returned to acting, playing lead character Ritchie in the phenomenal drama It’s a Sin, which came out in early 2021. Ritchie is a young man who moves to London and hits the gay scene just as Aids arrives in the UK. We watch as tragedy after tragedy unfolds over the course of a decade. The show captured joy as well as pain, though, and Alexander’s impish spirit fed into Ritchie’s outlandishness and vulnerability. He has just been nominated for a US Critics’ Choice TV award for best actor in a limited series, for which he will compete with Paul Bettany and Michael Keaton. It has been quite the acting comeback.

But he hasn’t acted since It’s a Sin, and now he’s here with a third Years & Years album, written during lockdown and recorded solo. He found lockdown hard, he explains, though he is careful to point out that, relatively speaking, he had an easy time of it. But he was living alone; he suddenly stopped working for the first time in years, and felt the weight of what he describes as “the world imploding”. Normally, he loves his own company. “I actually crave alone time. But then having all of it in one go was just … it was quite overwhelming,” he says.

Alexander has been frank about his mental health in the past. In 2017, he made a moving, raw documentary for BBC Three called Growing Up Gay, in which he talked about mental health in the LGBTQ+ community, and shared his own experiences of being bullied and feeling ashamed of who he is. He talked about bulimia and self-harm, some of which was news to his mother, who heard about it for the first time on camera.

He is something of an open book, I note. “I know! It’s all out there. I just think, ‘God, there’s nothing else I can say.’ It’s a compulsion, I think, more than anything else. Not to pathologise it or anything.” Alexander made a decision to be honest about who he was from the very beginning, when people first started to pay attention to Years & Years. “If people are going to ask about sexuality or mental health, then what am I going to say? If you’re honest, you don’t have anything to hide. Everyone deals with it differently, but I thought, ‘OK, I’ll try that.’”

Just before Years & Years released their debut album in 2015, Alexander, then a rarity as an out male pop star clearly singing about men, expressed his sadness that there weren’t more like him. While there hasn’t exactly been an avalanche of male-on-male love songs, Lil Nas X, the singer and rapper who is gay and who gave the devil a lapdance in his video for Montero, has ascended to the pop throne and is now one of the biggest pop stars in the world. Does Alexander think there has been a shift? “When Lil Nas X went to No 1, I literally felt like running down the street naked, screaming in celebration, because it was such a huge moment for me,” he says. “I had begun to think, ‘God, will it ever happen? Will we ever get someone that is this huge crossover star, who’s gay?’ I just think it’s incredible, what he’s done. I’m in awe.”

After 10 years together, Years & Years have gone from being a three-piece, comprised of Alexander, Mikey Goldsworthy and Emre Türkmen, to a solo act. But rather than start releasing music under his own name, Alexander has kept the Years & Years moniker. “I just didn’t want to let Years & Years go. I put so much into it. It was a tricky decision in some ways, because I think, possibly, it might have been a bit simpler for everyone if I had just been like, ‘Oh, I’m a solo artist now.’ But I just didn’t want to.”

The official line is that the split was amicable. “The new album has been an Olly endeavour and we’ve decided that Years & Years will continue as an Olly solo project,” read a statement put out by the band last March, adding: “The three of us are still good friends.” Goldsworthy will be playing live with Alexander when the band goes on tour.

But band break-ups are rarely so clean. “Bands are like marriages,” Alexander says. “Any separation is difficult, and I think it went as well as it could, with us.” He first joined Years & Years in 2010, and there is a strong sense that he was calling the shots from the beginning. “They didn’t really have a singer. And I came in, and I was like, ‘No, I’m the singer, I’ll be writing songs.’ So you can see, over that trajectory, perhaps this was sort of inevitable.”

By the time of their second album, Palo Santo, in 2018, Alexander’s red hair had arrived. He was starting to become more pop star than indie-pop star, and it became clear that the band had different ideas about what their music would sound like. “Early on, we were more or less on the same ship, trying to steer in the same direction, and then just clearly we weren’t any more.” He sighs. “It was definitely the best thing for us, to go our separate ways, rather than try to make it work.”

Which different directions had you all started to go in? “Well, I love pop music. I wanted us to play our song on The X Factor, for instance. Not that that ever happened – we didn’t get booked. But that was a huge issue within the group, because that felt like it would be too pop, and that being on TV like that was kind of lame.” There were the familiar “musical differences”, too. “When you think of a band, you imagine them all together in a house making music and coming up with ideas like that. But that was never how we did it. It was always quite separate, and then you figure out a way where you all feel good about it. After the first album, we never felt good about anything as a band. That’s when it all started, really.” He says he was proud of Palo Santo. “But it was not loved by everyone in the band, and that was hard for me.” The three of them still got on well enough to go on tour and have a good time, he says. “And obviously, I don’t want to speak for them, because I can’t.” But it sounds as if the split wasn’t a huge surprise. “It was coming for a long time.”

***

Around the time that Years & Years were coming apart, he was making It’s a Sin in Manchester. It was an experience he loved, but one that was, he says, incredibly intense. For one thing, during a short break in filming, over Christmas 2019, his grandmother Rosemarie died. She had been a singer in her youth: she was a chorus girl who went to New York to perform and had a few leading roles on stage. She was his mother’s mother, and they were extremely close. “I was with her when she died, and then went back to work, and then came off that, and then the pandemic felt like it happened straight away. I hadn’t processed my gran’s death, really. And then I was thinking, ‘Oh my God, I’m trying to make this pop album. What’s the point? What is actually the point? Does anyone need another pop album? Not really.’” He giggles nervously. “I was having all those thoughts.”

Then he turned 30, in July 2020, just as the first set of lockdown restrictions began to ease. “Maybe it sounds a bit silly, but it really felt like quite an achievement, to be 30. When you’re younger, you don’t ever imagine you’ll get to 30.” It felt, to him, like the first “big age”. Once he’d passed 25, he started to realise that he liked himself a bit more. “I was feeling like, ‘OK, maybe something is working here. I may finally be able to be a bit more at peace with myself and have a more solid foundation.’ And in terms of feeling like I’m too old, I felt too old when I was 27, 28, and coming back with the second Years & Years album. I found the transition from being ‘the young one’ really hard. I was looking at other pop stars who were in their early 20s, and I was thinking, ‘Oh my God, I’m ageing out of this. Like, I’m too old!’” I can’t help but laugh; he is still the picture of youth. “I know! It’s crazy. But that’s how it felt. Like, ‘Oh no, I’m past it!’”

That feeling has quietened down. He celebrated his 30th with a trip to the treetop rope-bridge experience Go Ape, of all places (“the perfect thing for me: activity, outdoors, slightly scary”) and a nice meal, and he is much more comfortable with himself. “I feel so much more at peace with myself than I ever did,” he nods. “I’m just holding on to that feeling.” Why is that? “Time helps, you know.” He pauses, then adds, with a cackle, “And I’ve had a lot of therapy.”

Eventually, Alexander decided that even if the world didn’t need another pop album, he was going to make one. Night Call sounds as if it burst out of lockdown. There are no slowies, no ballads, only bangers. “All I wanted to make was uptempo music you could dance to in a club,” he says. It’s a tribute to nightlife and freedom, and the sex that can go with it. On one song, he sings about “All that muscle, getting me into trouble … ” Another, 20 Minutes, celebrates the joy of a fleeting sexual encounter. “A lot of the songs are about sex and hookups because it was something that was absent from my life,” he says, laughing. “I was trying to manifest some physical contact and thinking about the past few years before lockdown. It’s not like I was having tons of sex, but I was having some sex.” He found that he was inspired by the different ways in which people express desire, including himself. “I thought, I can write songs about this.”

He pauses on the edge of saying something, trying to work out whether he should or not, then decides to jump off. “But I have to say, um, that I’m lucky that I do have someone that I like – love, actually – a lot. Who loves me back.” He claps his hands, joyfully. “So that’s nice!”

Is it a new thing? “It’s not actually a new thing. I’ve known him for six, seven years, I think. Over that time, we’ve called our relationship different things, if that makes any sense. And now we don’t have a name for it. But he really supports me. Over the past year, I’ve really leaned on him a lot. I’m going to be super private about him, but that’s part of my story, so I have to say it.” Is he your boyfriend? “I’m just not … ” Defining it? “I’m not defining it.” To me, or in general? “I mean, we talk about this kind of thing a lot, but it’s like the word is too much, or something, so I’m not going to put it out there.” So the hookups you’re singing about on the album are a past life? “No. I mean, I still hope to hook up again, some day,” he grins. “We’re not in that situation.” We both start to laugh. “It’s complicated, isn’t it, all that stuff?”

Night Call is about dancing and shagging and hedonism. You can practically feel the sticky floor underfoot when you listen to it. “What I love so much about dance music and disco is that idea of liberation on the dancefloor. It’s communal, you come together and feel free, to the beat,” he says. In some ways, I suggest, it feels like a companion piece to It’s a Sin. “Definitely. It became super-present in my head,” he says.

Russell T Davies, who wrote and created It’s a Sin, says he only auditioned one actor for the part of Ritchie, and that was Alexander. Davies is about to return to Doctor Who as its showrunner, but before that was announced, Alexander found himself on the front page of the Sun, being announced as the new Doctor. How did that happen? “It genuinely was news to me, I promise you,” he says. We gossip for a bit, off the record, but he insists he isn’t doing it. “I definitely am not Doctor Who, and I’m not going to be Doctor Who,” he says. I fix him with a stare. “Promise!” Really? “It’s not happening! I can tell you I’m definitely not doing it.”

***

In It’s a Sin, Ritchie moves to London from the Isle of Wight to become an actor, and arrives with gusto on the city’s gay scene, partying and sleeping his way around town. When Aids begins to tear through his social circle, he is in denial, at one point giving a petulant speech accusing the government of fear-mongering and trying to stop gay men having sex. He values his freedom as a gay man; he votes for Thatcher. He is afraid and he is defiant. He is a complicated character, which makes his story all the more affecting. It feels authentic.

Given that Alexander moved to London (from Gloucestershire) at 18 to become an actor, there are parallels, aren’t there? “For sure. Except he’s a fucking Tory,” he jokes. “I’m so angry at Russell! Making me play a Tory on TV.” What does he think Davies saw in him? “I don’t know. But it’s not often you see a character that’s so connected to your life that’s gay, that had these big ambitions, that was hiding something from the people around him. I felt all of those things. So I thought, ‘Oh yeah, I could do this. I can get into his head.’”

He put acting on the back burner for Years & Years, and hadn’t acted for six years when It’s A Sin came along. He was intimidated. “I just thought, ‘What have I got myself in for, thinking I could do this?’ I was doing well as an actor, but I had never read something like It’s a Sin. You could wait your whole career and not get something as good as that, so I was like, ‘I have to do it, and do a good job.’”

The reaction made it clear that he pulled it off. The programme won over critics and audiences in the UK and in the US. Unsurprisingly, for a drama about the Aids crisis in Britain, one that so tenderly and furiously memorialised the lives that were lost, it was devastating. Alexander often cried while reading the script and when learning his lines. “I know a lot of us on set felt the same. So I suppose it isn’t surprising that some people were similarly affected by watching it, or had an intense response. I hadn’t realised how much of a shadow it had been for lots of people, and the need they had to cast some light on it and say, ‘I was there, I remember it.’” He was born in 1990; it wasn’t his world. By playing Ritchie, he was just bearing witness to it. “But what to do next with that? I don’t really know.”

Alexander says that at times he found the public reaction to It’s a Sin “overwhelming”. “My favourite word,” he smiles, a little sadly. “I felt like maybe some of what people experienced watching the show, I went through it in my own way, just by learning more about the history, because there were huge gaps in my knowledge of what happened in the UK in the 80s. That was a really deep, profound experience for me, as a human, but also as a gay man. It felt like it contextualised a lot of my experiences growing up.”

Even now, Alexander still gets messages from people who have seen Growing Up Gay and identified with the struggles he went through as a young, closeted teenager who was bullied at school. It is a powerful film that distills complicated ideas about shame and internalised homophobia, for example, into a deceptively breezy format. “I’m glad you say that because obviously these things are so complicated and so different for everyone,” he says. “It’s so weird to be in a position of spokesperson or representative in any way of my community, as a gay man. You bump up against so many issues, like representation politics. But I think if you can give people some of the foundations of an idea or concept or a way to discuss something, even if it’s just an opening, then people can do the rest themselves. That’s a good thing, I think.”

I wonder if the documentary is similar to It’s a Sin, in terms of it opening him up to hear about other people’s pain? “Mmm,” he says. “It’s hard, sometimes. I’m just trying to figure out a way of answering you and not crying myself, right now.”

But he starts to cry, anyway. “This is what I mean, when it’s overwhelming, because you see how much people are in pain,” he says, his voice wobbling. “It’s sad to see that. And obviously I am someone that feels that stuff, too. And it just comes out like this.” I give him a hug. “Sorry,” he smiles. “It happens a lot. Like, in every interview, to be honest.” It’s not just me? “Don’t think you’re special!”

He composes himself, carries on. “You know, I do these quite big, exposing things. Like, even It’s a Sin, obviously I’m playing a character, but then I have to really step back from it.” How does he do that? “I think of it happening slightly separately to me. It’s all part of something that is connected to me, but it’s all part of something else as well. And I still can’t quite figure that out. But that feels so much larger than me, Olly, and what I can contain in my brain, day to day.”

Pop star duties are calling Alexander. He has Years & Years CDs on his kitchen table that he needs to sign, some social media posts to do to promote his latest single. I ask if he’ll return to acting soon. He hesitates. “I think I will, yeah,” he says. “When it’s something I want to do.” But he doesn’t exactly sound desperate to do it. “I know! Haha. I’m not, really. It’s such a bizarre job. And I feel like I left it behind for a reason, to make music and do Years & Years. It’s a Sin reminded me of how incredible that circus can be, so it would be fun to do again. But I’m just going to wait until it’s the right thing. Or make my own thing, at some point.” What would you make? “Like a queer horror thing? I love horror. Something in the vein of Twin Peaks, or Mulholland Drive.”

Alexander once said that he had planned out his life until he was 25. Is there a new plan in place now? “No plan any more,” he says easily, but then he changes his mind. “Actually, have you seen Grace and Frankie?” He’s talking about the Netflix show starring Jane Fonda and Lily Tomlin. “I just love their setup. They’re two women who are best friends living in this gorgeous place by the sea, in their 80s, still having sex, getting stoned and getting up to all sorts of trouble.” He grins. “My vague plan is to end up with something like that.”

• Night Call will be released on 21 January.