She may not have burst, fully formed, from the jazz hands of Bonnie Langford mid-Cabaret, but Eliza Doolittle couldn't be more stage school. She's the granddaughter of Sylvia Young, the daughter of a couple who met while working on the original run of Les Misérables, and a child star of the same musical, aged eight. A few of those luvvy affectations have trailed her into womanhood: the odd hammy shiver, the air of revue and glints of showtune, the yoof-soul voice set midway between the Albert Hall and Poundland.

Yet tonight, this soul-pop slinkstress seems more authentic, dues-paid and autonomous – less bought-in – than the Emeli Sandés and Tom Odells of the Brit-pop mainstream. Her shout-outs are to pub-circuit stalwart turned Florence collaborator Kid Harpoon, whereas her gorgeous three-part harmony medley of cherished songs from her childhood includes Blink-182's All the Small Things. Her forthcoming second album is even more intriguing, marked as it is with emotional scars following her breakup with Benji Madden from Good Charlotte. The Day-Glo fashions of her self-titled 2010 debut may have given way to a Jessie Ware make-under, but she remains refreshingly unstyled.

Crucially, she relies more on melody than dynamic to carry her songs, whether tripping through early package-holiday pool-volleyball anthems Skinny Genes and Mr Medicine, swapping her stack heels for sneakers for a solo piano version of her Disclosure collaboration, You & Me or pouring her heart over the brim of the stage during the affecting new ballad One in the Bed.

Doolittle's failing tonight is merely a lack of major hits; only the reggae-lite Pack Up has bothered the top five, and then only on the back of a Kinder Surprise advert and its nagging resemblance to Bobby McFerrin's Don't Worry, Be Happy. But in the irresistible hookline of new single Big When I Was Little, she's found her Henry Higgins. Now get her to the charts on time.

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