On paper a concert by Antony Hegarty backed by a 60-piece orchestra might not seem a good idea. Hegarty's bittersweet mood of self-absorption (sample lyric from Cripple and the Starfish: “I am so very happy/ So please hit me”) slathered in strings could teeter into mawkishness. This, though, does not happen, and that's largely because of the sensitive, striking orchestrations of Nico Mulhy, a young collaborator with Philip Glass, who couches Hegarty's fluttering contralto in vivid settings using the full resources of the London Symphony Orchestra.

For his first British concert in three years, Hegarty is clad in a grey toga (an apt compromise for someone who muddles gender stereotypes). During the first two and a half songs he is unlit, a towering silhouette from which gentle yearnings emerge. He's part Morrissey, part Nina Simone, and as the lights slowly brighten, he begins to accompany songs with fragile, birdlike gestures. Later, with arms outstretched on the dissonant Everything is New, there's even a hint of Jessye Norman.

Much of the set is from his next album, The Crying Light, due in January - songs of rapture and redemption in settings that move from American minimalism to the operatic rumblings of brass and double bass. The audience, though, is delighted to recognise For Today I'm a Boy with its new symphonic sweep. Another World, the title track of his new EP, is already reinvented, unfurling over a long minor chord. In (Fell in Love with a) Dead Boy the orchestra suddenly halts for perhaps 30 seconds and Hegarty stands frozen. It's a moment of drama, audience and performers locked in silence before the strings gently resume.

But then the mood of reverence is broken. First there are stray giggles, then a burst of applause as Hegarty launches into Beyoncé's Crazy in Love in a sudden surge of rhythm. It's odd but effective.

The slow majesty of Her Eyes are Underneath the Ground brings the set to a close; the stage lights swivel towards the audience and the double basses growl to a Wagnerian climax. There's one encore, River of Sorrow, dedicated to Marsha P. Johnson, the New York transgender activist who inspired Hegarty and gave his band its name.

It's a beautifully wrought show. From Brian Wilson on, pop musicians have periodically aspired to the emotional clout and textural subtlety of art music and lieder; Hegarty has got closer than most.

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