As monumental vanity projects go, this one is surprisingly absorbing. It is also intermittently excruciating. In in-i Akram Khan, the British-Asian dance wunderkind, meets and merges skills with the Oscar-winning French actress Juliette Binoche. Working with a dramaturge but functioning as co-directors, this starry pair have concocted a 70-minute performance featuring movement and text loosely - and self-indulgently - spun round the theme of love.

A massive free-standing wall designed by Anish Kapoor and lit with typical boldness and sensitivity by Michael Hulls, dominates the stage. Initially Khan and Binoche slip past it and enact a little scenario - set to her narration, in English - about seduction in a cinema. With clingy, predatory persistence she captures him, the cue for a bit of buttock grabbing, a few hot kisses and simulated copulation up against the wall. Then comes the aftermath: troubled sleep and a downward spiral into domestic irritation centred on - I kid you not - the couple's mimed toilet habits, with another spot of rote-like intercourse thrown in. Meant to be cutely ironic, it is also dishearteningly coarse.

This flimsy, navel-gazing show, like their onstage relationship, proceeds bumpily. Binoche expresses ironic disillusionment by singing snatches of The Man I Love during a tango. Eventually she and Khan, a bottled-up brute, argue in an overblown, quasi-therapeutic fashion. Their pained - and painful to hear - banalities remind you why playwrights exist.

Although as an adolescent he appeared in Peter Brook's epic Mahabharata, Khan is not celebrated as an actor. But he has used the spoken word in previous dance-theatre productions. After the blow-up with Binoche he delivers, and more than passably, a possibly autobiographical monologue detailing the blasphemous frustrations of a brown-skinned boy drawn beyond the circumscriptions of the faith in which he was raised.

Khan is plainly pushing his abilities here, but the bigger stretch may be Binoche's. She is not known for her dancing, and yet she more than holds her own alongside the muscular, contained whirlwind that Khan becomes when in motion. Spinning, striding and swiping at her partner or the air, she invests herself in the movement with an emotional daring many trained dancers lack. The roughly intimate, visceral drama of their duets compensates for another of the evening's partial embarrassments, a monologue by Binoche about abuse that sounds and feels undigested, unshaped. When she shuts up and gets physical, she rocks.

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