It's about half an hour before she's due on-stage, and Lianne La Havas is leaning out of the second floor window of Brixton Academy, shouting gleefully down to her friends on the street below. Just around the corner, unaware of what's happening, thousands of fans are queueing up to see her perform.
When she arrives on-stage later, the nervous energy that exuded from that second floor window is gone. It's been replaced by a calm and commanding presence, as La Havas stands, guitar in hand, in a silver sequinned dress that sends shards of light across the room like a disco ball.
She opens with 'Green & Gold' - a nostalgic ode to the innocence and uncertainty of youth. In it, she imagines her six-year-old self, "trying to dip my toes in the mirror[...] Thinking where am I gonna be / If I'm ever twenty-three?" At 26, she's surpassed her childhood self's definition of adulthood - but it's doubtful even the most childishly optimistic daydreams of that six-year-old would have placed her here, at Brixton Academy.
In fact, it's only been four years since she stood on the other side of the barriers, watching Erykah Badu perform. "I think, genuinely, that it changed my life," she says of the gig, as she finishes 'Wonderful', which she's transformed into a duet with opening act Kennan O’Meara, "and London made my life." If it sounds a little glib on paper, it's spoken with an earnest warmth.
Though she plays a mean guitar (particularly on the crunching, rocky 'Never Get Enough'), it's La Havas' voice that curls itself most rivetingly around the room. Airiness isn't a quality singers tends to strive for, but hers is a rich, mellow airiness - as if she's pouring a little portion of her soul into every note.
"I'm trying very, very hard to remain calm," she beams, after working a reimagined and reinvigorated version of Pharrell's 'Happy' into the middle of 'Au Cinema', "I find that singing helps."
No wonder, with a voice like that.