As performers, they're night and day. While Guillem is tall, slim and awfully supple, Khan is short, quick and a noted exponent of north Indian kathak. This 70-minute show sees her bending and knotting her long, balletic lines into the grooves of his compact muscularity, their duets shaded with discord and harmony inside Japanese set designer Shizuka Hariu's curved glacial walls.

With both their hands joined, they swoop across the stage as their linked arms weave around them in waves and arcs. Soon, they're play-fighting in slow-motion and trading blows. She corners him. He sends her rolling backwards onto the floor with a few mock head-butts. This note of conflict in their first dance continues in their next one, which takes on a more comic tone. Jerking their limbs one joint at a time, Guillem and Khan battle each other as feuding puppet-lovers.

These encounters, as well as their casual banter in between their dancing, reveal a disarming sense of humour that, despite their star power, bring them down to earth just a bit. They, too, have their nagging doubts. As a classical dancer, Khan tells us, can he still portray the curly-haired Hindu god Krishna when he is balding? Guillem worries about being futile: "What I do is fine and I love doing it, but is it really important?" she asks while shifting herself objectively into various lying and sitting positions.

Supporting the action is a lean, textured score by composer-cellist Philip Sheppard, who plays it live with a quartet of musicians and singers. Sometimes it works quietly in the background, muted to a smattering of whispers; it also expands with entrancing melodies, as it does during the second half of Monsters. In a surprisingly tender duet, Khan and Guillem - her legs hooked around his waist - echo each other in large, undulating gestures that recall Hindu statues. By the end, they're exchanging dance steps with the fresh-faced joy of finding themselves anew. It's a strikingly touching scene.

Guillem's solo at the start of the show doesn't have quite the same sparkle, though it showcases her famed technique and leggy, ear-grazing extensions. Made by Cloud Gate Dance Theatre guru Lin Hwai-min, it presses her to the ground in low, crouching poses; the arms unfold branch-like. She may lack a more dynamic sense of weight for this dance, but she can make a turning kick look all the more beautiful.

Khan, on the other hand, gleams in a solo created by kathak master Gauri Sharma Tripathi. The coruscating rhythms of his stamping feet, the angles and coiling vines that he shapes with his arms and hands, the sudden corkscrew of a pirouette - when there is dancing this good, who cares about the hair?