How does she do it? Somehow, Lizz Wright is turning an early evening concert at the Purcell Room into an intimate, after-hours club. With a small, mainly acoustic band and some subtle lighting - which casts her statuesque silhouette on the side wall - the self-possessed young singer makes the South Bank's chilliest venue feel like a soiree for friends.

The timbre of her voice is what strikes you first - rich and strong, infused with gospel and the vocal heritage of jazz. She has a warm, attractive presence: sincere and not overly chatty but not shy. When she says a few words about the way that music is made by everybody in the room, and how much she appreciates our close attention to the music, everyone in the sold-out house returns her love tenfold.

The accompaniment is pretty minimal compared to that of her debut album Salt. There's Carl Burnett (acoustic guitar), Jon Cowherd (acoustic and electric pianos) and Jeffrey Haynes (hand percussion). Wright also strums a guitar for several numbers before standing to perform a highly original arrangement of Nature Boy for voice and percussion.

The colourful kit - djembe, congas, timbales and cymbals - leaves space to hear the range of Wright's vocals.

Haynes, a regular collaborator with Cassandra Wilson, is an unstoppable source of energy, whether beating out an intense pulse on cajon or playing right across his unconventional kit. He even attacks the outer shell of his kick drum during an exuberant solo slot. But it is Wright's show. She has the ability to get right inside her material: the cool funk gospel of Walk With Me, Lord; a re-interpreted Narrow Daylight (by Krall and Costello) accompanied by grand piano; the spacey acoustic funk of Chick Corea and Neville Potter's Open Your Eyes You Can Fly, the Flora Purim song she's made her own. Wright has an enviable ability to make focused, commercial music of great honesty. She's the real thing, and that's jazz.