Giselle, Royal Opera House, London <!-- none onestar twostar threestar fourstar -->

Stepping out of her cottage, Giselle starts to dance for the pure pleasure of it. Darcey Bussell moves with expansive delight, with big, glowing lines and a soaring jump. She's the centre of the ballet's world.

Yet Bussell, who danced her first Giselle in 1995, isn't obvious casting. This Romantic ballet has a fragile heroine, a village girl who falls for a disguised aristocrat. When she finds that he has lied to her, she goes mad, dies, and returns as a ghost. The tall, athletic Bussell isn't obviously frail or ethereal, nor has she much reputation as an actress.

So much for typecasting. Bussell's village girl is immediately real, with a freshness that lifts the ponderous naturalism of Peter Wright's production. It's true that Bussell can be a limited actress, but she also seems to "find" herself in certain roles, when her responses become quick and natural. Her Giselle, like her Cinderella, has an unexpected pragmatic streak. When Albrecht approaches her, she looks him over seriously. Bussell makes her petal-counting, playing "he loves me, he loves me not", look down-to-earth. Accepting him, she dances with new lustre, extra happiness. Roberto Bolle isn't a deep or subtle Albrecht, but he fills his place in the story. He looks princely and dances with polish.

Bussell pays attention to everyone else on stage, with gentle care for their feelings. Her relationship with her mother, danced by Genesia Rosato, is particularly close. The dancing is fluent and gorgeously phrased. In one diagonal, Giselle hops on pointe, her eyes looking up, then shyly down. Bussell builds the hops into a steady sweep, feet strong and stretched: love of dancing carries her forward, even as her upper body shows her changing emotions.

The second act is weaker. A few distortions creep into Bussell's dancing, high leg extensions tugging at her phrasing. A few of these steps lose their weightlessness on Bussell's tall body, but her jumps are ardent, windblown. And it's good to see such pure line in this ballet: the Royal's first-cast Giselle, Tamara Rojo, was worryingly unclassical.

This is Bussell's last season as a full-time principal with the Royal Ballet, though she will be a guest artist next season. She's gone in and out of critical favour, partly because she's an uneven performer: her marvellous physical gifts aren't always coherently used. In this Giselle, she's dancing with full maturity.

To 29 April (020-7304 4000)