When Xingxi Wang started running K-pop dance classes in Birmingham, she rented a small room in Chinatown. Within a few years, demand had grown so much that she was able to open her own studio where she now runs up to 10 classes a week.

Like many K-pop fans, Wang, 25, has been teaching herself dance routines at home since she was a teenager at school. Slick, synchronised choreography is a key component of K-pop, along with the fashionable outfits and synthesised music that define the genre.

“I didn’t realise how popular it would be when I started, but I found out there are so many people who want to come to K-pop dance classes,” Wang said. “So I decided to create my own K-pop studio. We’ve had to set up a maximum number of people for each class as we’ve had so many people wanting to join.”

When the Guardian went along to try a class, it was busy for a rainy Thursday evening, with about 12 women in the studio. They had varying levels of dance experience and were united by all being big K-pop fans.

K-pop artists have been growing in prominence in the UK in recent years. In June, Seventeen became the first K-pop band to play at Glastonbury. BTS were the first K-pop band to headline Wembley Stadium, in 2019, and Blackpink have headlined BST Hyde Park.

The genre’s global reach is huge: four of the top 10 bestselling acts in 2023 came from South Korea, according to the music industry body IFPI.

Dance classes have been springing up in response to K-pop’s growing popularity. There are dozens across the UK, mainly concentrated in London but growing elsewhere, too.

Wang has about 10 part-time instructors at Xi Dance Studio, where dancers learn the choreography for a song by one of the big K-pop stars at each class. They’re divided into girl group and boy group classes, and those for some of the biggest bands, such as BTS and Blackpink, sell out quickly.

In preparation for each session, Wang will spend hours analysing music videos online to learn the moves, and then break it down into counts so she is able to teach it to everyone from experienced dancers to beginners.

“I record the original video and then I have to mirror it and use slow speeds as I am learning it. I’ll watch it hundreds of times, for one dance. For today’s dance I spent many hours preparing,” she said.

It means that in each session, dancers are learning the exact same steps as the stars they idolise. “The idea is to make people feel like they’re in a band. If we’re learning a Blackpink song I will say: ‘OK, you are Blackpink, you’re on stage and you’re going to perform, just trust yourself,’” Wang said. “And you can see people grow in confidence.”

On Thursday evening, dancers were learning the choreography to Go Hard by the band Twice, a nine-piece girl group who rose to fame in 2016.

The song, with lyrics in a mixture of Korean and English, is an upbeat and feisty dance track with empowering lyrics – “I’m unstoppable … woman in the mirror,” they sing.

Standing in front of the big studio mirror, Wang takes everyone through a warm-up and then the routine in bite-size chunks. There’s lots of body rolls and hip pops, culminating in a triumphant fist pump.

“Now let’s try it full speed,” Wang announces. The song and choreography ratchet up a couple of notches and the steps move quickly – a squat quickly followed by a spin and a body roll.

As a non-experienced dancer, it’s tricky to keep up but the fun is in throwing yourself into it regardless and hitting as many beats as you can.

They are the exact same moves you can see Twice doing on their music video for the song, silhouetted against a neon backdrop, and many of the dancers in the room clearly love the feeling of emulating being in a girl band.

Some in the room are complete beginners and some have been coming to the studio for years – such as Yuxi Xiong, 23, who travels from Coventry twice a week for the classes.

“I love K-pop and learning the dances – it’s my hobby and a good way to stay healthy,” she said. “I will take videos with my friends of us doing the dances, so I practise outside class too.”

She said the classes had got busier in recent months as K-pop grows in popularity. “I like that, it makes for a good atmosphere in class and I like being able to perform in front of people,” she said. “I like lots of girl groups from Korea so I normally look at the class schedule and pick my favourite songs to come along to.”

At the end of each class, the dancers do a final performance, which is recorded, and they’re encouraged to go all-out. “K-pop dance nowadays is not easy, because they mix different styles like jazz, funk, hip-hop in one dance. So it’s not easy to just learn by yourself, and I think that’s why people like to come to the classes,” Wang said.

“K-pop is just so popular now, the bands really promote themselves on the global market. The classes just keep growing.”