Genuinely classy singers invariably place the needs of the song before their own desire to show off. Cape Verde's "Barefoot Diva", Cesaria Evora, is one such singer. Her melancholy voice hangs heavy in the air like a storm cloud, yet it never seeks to draw attention to itself. It's an admirably ego-less approach that allows her to inhabit the skins of female and male narrators, but when you combine it with her near invisibility as a stage performer you occasionally find yourself hankering after something a little more personal.
Evora sings morna, a form of Cape Verdean blues that bears a passing resemblance to Portuguese fado. Unlike that music's most famous current performer, Mariza, Evora makes no attempt to dramatise the internal action of the songs. In fact, for the first hour of the concert she makes no attempt even to say "Hello".
To be fair, this is all part of the act. Like her bare-footedness, Evora's gloomy demeanour is designed to remind us of the harsh realities of her homeland. Yet in the setting of a grand concert hall, she appears crabby and unwelcoming. Is she enjoying herself? Is she glad we're all here? As she slumps into a chair for her customary public smoke (to deafening applause, mysteriously), it is difficult to tell. Apart from a brief moment when she barks out the names of her rather fine eight-piece backing band, she remains studiously uninvolved with her audience.
Which leaves the music. Fortunately, much of it is beautiful. Africa, Brazil and Cuba all make themselves heard in the gently shuffling rhythms, while the guitarist and clarinettist make even the simplest runs a goose-pimple-inducing experience. An evening of controlled musical euphoria, despite the reticence of the star performer.
· At Usher Hall, Edinburgh, tonight. Box office: 0131-228 1155.