Genre-hopping is hardly a new pastime for celebrity vocalists - Barbara Streisand once recorded Schumann. Lesley Garrett has admitted that her current tour represents an experiment.
Judging from this capacity audience, it's one in which plenty of listeners are willing to participate.
There was no orchestra. Instead, subdued lighting and a five-piece jazz combo - directed by Tolga Kashif - signalled Garrett's new direction. "No, this isn't the CBSO" she joked, during a first half devoted largely to French cabaret repertoire.
This proved to be much the most interesting part of the evening. Disingenuously, Garrett announced that she doesn't discriminate between genres; yet by following Falla's Nana with another lullaby, Gershwin's Summertime, she illuminated both songs.
Placing Massenet's Adieu notre petite table between Jacques Brel and Edith Piaf likewise revealed a lively musical imagination. La Vie en rose was delicious, delivered with a sweet-toned tenderness that returned this cabaret standard to the French operetta tradition. And Garrett is our most natural operetta soprano.
But an operetta soprano she remains - and this became more of a problem after the interval. Again and again, in a string of show and film tunes, Garrett began idiomatically.
But as the refrain approached, the gestures grew more theatrical, the voice swelled and the vibrato opened out to full operatic power. Amplification meant that the familiar virtues and failings of that voice were startlingly magnified.
It was surely Garrett's personal charm that won her a standing ovation.
A wonderfully entertaining experiment, certainly - but only 50 per cent successful.