Bebel Gilberto is, to use one of her favourite words, nice. A lot of people think so. Tanto Tempo, her album of electronically enhanced bossa nova, sold over a million copies. This year's eponymous follow-up has been hailed as "balm for the senses" and "heaven on earth". Her British fans are out in force tonight, and they're nice too: nice people having nice chats on nice subjects.

What's not nice is that they're talking over the singer. Gilberto's critics sneer that she makes background music, and tonight her admirers seem to agree.

Yet Joao Gilberto's daughter and her band are worth listening to. Under a sky of cloud and seagulls, they play tunes that are at worst silk-smooth and at best stirring: new numbers like Simplesmente, which opens the show, and crowd-pleasers like Close Your Eyes, which ends it. The six musicians are committed and technically perfect, above all percussionist Davi Vieira and guitarist Pedro Baby Gomes. Winter is dreamily touching, Gilberto's breathiness perfectly matched by Gomes's hesitant guitar; the funked-up, percussion-heavy Bananeira is catchiness itself; Close Your Eyes is so fast and furious that the singer struggles to keep up with the band. And there's plenty to look at. Gilberto is a big bouncy Brazilian firecracker, by turns coy and flirty, pensive and exuberant.

To be honest, she tries a little too hard. She does a lot of rock-star claps, hands above her head, as if she were in a midwestern stadium. She thrusts her mic towards the crowd, who will cheer between numbers but won't chip in on the chorus. And she thanks everyone: her band, her record company ("for making me feel so special"), photographer Mario Testino (for making her look so good), the lighting technicians, Somerset House (twice), her producers, her manager, the front-of-house team ... even, shamefully, the audience - "absolutely, absolutely, absolutely the best".

Please, Bebel - you're making us blush. We really, really, really don't deserve it.