Antony and the Johnsons, Barbican, London

There's a fantastic image on the front cover of Antony and the Johnson's new EP of the great Japanese butoh dancer Kazuo Ohno. His face is caked in thick white stage paint; his fingers snap out of shape, almost audibly, and his eyes fix themselves on some chimerical vision just out of shot. As a caught moment of butoh's dance of darkness, it's an arresting image; as a frontispiece to Another World, five songs of crippled beauty and uneasy, otherworldly landscapes, it's a masterstroke.

Yet if the New Yorker's new raft of dark cabaret songs are peopled with ghosts and folklorish shape shifters, and hooked on transcendence and transformation, then Antony Hegarty himself, he of the absurdly affecting, ecstatic, harrowing voice, can hardly be accused of retreating inwards with his inestimable talents.

Since 2005's Mercury Music Prize-winning I Am a Bird Now, there have been turns with Björk and the New York disco-stompers Hercules and Love Affair, and lilting scores for Prada.

For Hegarty, though, a two-night shift with the London Symphony Orchestra may just represent a collaborative zenith. It's a crushing, mesmerising evening that in other hands may have been self-indulgent, but instead, thanks to Hegarty's modesty and innate sense of performance, is a revelation.

The LSO troop on stage first, then a quartet of Johnsons, and finally Hegarty himself. Centre stage, and entirely unlit, his swooping tenor creeps through the darkness, and with a rush of strings, two songs from his forthcoming album, The Crying Light, roll achingly by.

The LSO are on extraordinary form. Little space is left for some of the subtleties of Hegarty's musical turns, his quiet steps from major to minor, but for each dodged nuance, a rapping rhythm bashed out on the body of a cello or an orchestral full pelt takes its place. But it's Hegarty who grabs the spotlight. The best moment comes after a mighty "For Today I Am a Boy", when the LSO, the Johnsons and Hegarty himself stop dead for an interval of stillness and silence. Palpably, there's no void here, but a bellowing resonance and a vast space full of expectation as the audience hang, waiting for the next cascade of rising falsetto.

Yet for all the gravitas, there's still time for a nod and a wink. "This one's on the house," says Hegarty as he glides into Beyoncé's "Crazy in Love". It's a clever, joyful, soothing move that holds the secret to all art that prods at the gloom: a little look at the light.