Anne Teresa De Keersmaeker: Whatever you do, don't mention Pina Bausch...

Anne Teresa De Keersmaeker has helped define contemporary dance as we know it, writes Jenny Gilbert. But she isn't keen to talk about it

If you want to go on living, you don't step in front of a bus. And if you want to emerge from an encounter with Anne Teresa De Keersmaeker in one piece, you don't ask her if she's "the next Pina Bausch". It's not a reply you fear, so much as the silence that would follow, the queasy uncertainty of not knowing whether the question had been misheard, not heard at all, or judged beneath contempt.

For the record, any tendency in British minds to lump the Belgian choreographer with the German isn't entirely laziness. Like Bausch, Keersmaeker, 43, has been a dominant force in Europe's contemporary dance scene for more than 20 years. Like Bausch, she is small and dour in person, speaks barely above a whisper and seems to think smiling is for wimps. Her work attracts huge subsidy and resources - currently a full orchestra and chorus at Belgium's premier opera house, La Monnaie, as well as her own 13 dancers. And getting her to talk about it all is a bit like pulling teeth.

Yet we really ought to know Keersmaeker by now, given that her visit to this year's Dance Umbrella is her sixth, and she's been at other UK festivals too. But the fact that her company, Rosas, appears in so many different formats leaves its brand identity unclear. A visit to the Barbican last year brought the large-scale Rain involving 10 dancers and 18 musicians. This time, Rosas brings merely a solo (danced by the choreographer herself) at The Place, and a duet (Keersmaeker with her "travelling companion" Cynthia Loemij) on a scaled-down Sadler's Wells stage.

The duet, which bears the title Small Hands in reference to a poem of ee cummings, promises an unusually intimate evening, and not just because of the closeness of the action. Seeing the show in advance in Holland I was struck by the way the crepuscular blue light that pervades the piece makes you aware of the other people sitting watching. In turn, this changes how you feel about being a spectator yourself, it makes you involved and no longer anonymous.

And while the dancers stop short of actually sitting in your lap, you regularly feel the rush of wind as limbs are propelled within inches of your nose, or skirts brush past your knees. You become conscious of the dancers' breathing. And at the peak of their exertion you even sense them with your nose, and that's not as unpleasant as it sounds. "The closeness does make it special," Keersmaeker concedes.

Another thing that strikes you about Small Hands is how full of joy it is. Avant garde dance in the Low Countries isn't best known for being a bundle of fun, and Keersmaeker herself seems permanently disgruntled. But there's no denying that this 70-minute duet of hers is the equivalent of a date with a sun lamp. It even kicks off with a joke.

As Henry Purcell's radiant overture to "Welcome to All the Pleasures" strikes up, there is a scuffling offstage, a muffled curse as someone stubs their toe, then sounds of a frantic scramble as the two performers sprint down a labyrinth of backstage passageways, apparently caught out by their cue. And when they do make it, panting, into the arena, they carry on like two young girls out of bounds on a frolic. As Purcell's glorious court music bounds through its references to pleasure and delight, the pair race each other the full length of the arena. They hop, skip and jump with two feet like kangaroos, they roll like hedgehogs down a grassy bank, and they twirl on the spot to make their flimsy white dresses flare.

Oh yes, the white dresses, so innocent, so demure. Yet as your eyes get used to the lighting you realise the two women have nothing on underneath. Every time a leg flicks up you think you're about to see more than intended. But the effect is far too spontaneous to be a tease. Keersmaeker surprises me by agreeing. It was her decision to wear no underwear, she says. "I don't know, it looked quite... how do you say?... vulgar and coy to have knickers or bikini showing. To be naked under the dresses pushed forward this idea of being seen from all sides. There's no back or front to the stage. There's no place to hide, so you really show yourself." Showing oneself. That's what Keersmaeker seems to be on to. And at the climax of the evening both women throw off every stitch and run half a circuit unencumbered, before wriggling into different clothes and carrying on as before. "Clothes change the perception of human movement, no? I was interested to see how this happens." As for the style of the women's movements, it's so free you might think they are making it up as they go along, but for the fact that for the best part of 70 minutes they dance in immaculate unison. Why work so hard to make something look as if you haven't worked at it? "Well, I'm happy it looks so natural but there is a lot of technicity to it," says its creator. Emboldened by this fulsome reply, I chance a private opinion. Small Hands, I say, looks like the happiest piece she has made to date. "Happy?" Keersmaeker says, her brow clouding. "Happy? I don't know."

'Small Hands': Sadler's Wells, London EC1 (020 7863 8000), Wed to Fri. Keersmaeker's solo 'Once': The Place, London W1 (020 7387 0031), Sat and 19 Oct