It is rare to see such outrageous talent at such close quarters. Nearly a fortnight ago, Laura Mvula was performing a late-night Prom at the Albert Hall with Dutch jazz orchestra the Metropole Orkest. Tonight, at a benefit show for homeless charity Centrepoint, she is playing to 100 people in a tiny room tucked away in the upper recesses of a glitzy casino.

The supper-club setting suits her beautifully because Mvula is an artist who exudes intimacy. A striking figure, with a dazzling smile and a wayward Afro, she is a breathtakingly nuanced vocalist, coaxing her measured tones deep into the weft and weave of her self-composed material. Comparisons with Billie Holiday abound, but a better touchstone is the languid intensity and sublime phrasing of Sarah Vaughan.

Understated and free from melisma, Mvula fully inhabits her emotionally complex yet candid songs. Her voice implores, rebukes and seduces as the moment demands. Backed by an adroit string section, her pristine tones render She as fragile as the damaged soul it depicts; the jazzy Father, Father, about her parents' separation, is heartrending.

When songs glide to a close, the affable Mvula is all self-effacing Brummie charm, confiding, "I'm not very good at the in-between bits", and worrying aloud whether the crowd can see up her dress. Yet she possesses the innate charisma of the ferociously gifted, transforming the racked Make Me Lovely into a determined howl of defiance at the anguish of abandonment.

It's a gripping performance until Mvula lightens the mood with an encore croon of her "favourite song ever", Michael Jackson's Human Nature, accompanied only by her cello-playing younger brother, James Douglas. It's a suitably quixotic close to an evening that nobody wanted to end.

At Bestival, Isle of Wight, on 5 September. Box office: 0844 888 4410.