As You Like It, Wyndham's Theatre, London

More tragedy than comedy on the night that Sienna stepped out of Jude's shadow

This must be the first production of As You Like It where media anticipation has focused on the actress playing the secondary female role. But Celia - Rosalind's cousin and bosom chum - is portrayed here by Jude Law's 23-year-old fiancée, Sienna Miller, who brings to it all the ripe professional stage experience that can be mustered from appearing in three movies.

This must be the first production of As You Like It where media anticipation has focused on the actress playing the secondary female role. But Celia - Rosalind's cousin and bosom chum - is portrayed here by Jude Law's 23-year-old fiancée, Sienna Miller, who brings to it all the ripe professional stage experience that can be mustered from appearing in three movies.

For the privilege of losing her theatrical virginity in a plum Shakespearean part in the West End, she has had to wrestle with terrible handicaps. Her husband-to-be is the celebrity figurehead of the Young Vic's rebuilding campaign. This As You Like It is a Young Vic co-production, directed by its artistic chief, David Lan. Other actresses might have crumpled in the face of such adversity. Not Ms Miller. The question is: having demonstrated her mettle off-stage, how does she shape up on?

Well, let's put it this way - I once saw a 13-year-old girl give a subtler and more captivating performance as Celia in a school play. Limited to roughly two gestures, facial expressions, and tones of voice, wooden Ms Miller has repeatedly to resort to the amateur's tactic - ie, when in doubt, shout and exaggerate.

She approaches an emotion with the finesse of someone beating a carpet. As a result, there's precious little comedy or charm left in Celia's frustration at being sidelined by Rosalind's crossed-dressed mock-wooing of Orlando.

To be fair, Miller is not on her own in the incompetence stakes. It seems that a lack of experience in Shakespeare has been no bar to recruitment in the cast of Lan's production, which relocates the play in 1940s France. The banished Duke Senior (Clive Rowe) and his courtiers appear to be a group of exiled musicians, who regale the forest with sophisticated Gallic melancholy and occasionally double, using umbrella handles for horns, as the pastoral flocks - albeit sheepishly, so to speak, because this interpretation of the play does not exactly radiate a strong sense of company or enlivening self-conviction.

The stand-up comic Sean Hughes offers a flaccid, sanitised take on the fool Touchstone and fails to suggest his slippery relativism. Reece Shearsmith (of The League of Gentlemen) is a stroppy nonentity rather than a convincingly philosophical cynic as Jaques. It's no help that his "seven ages of man" speech has been shifted so that it now does not have its undercutting pay-off, just as it's not a smart idea to have the pairs of lovers so categorically upstaged at the end by a singing, campy, stage-struck Hymen.

The greatest pity is that the production reduces the excellent actress Helen McCrory into lapses of overemphasis as a deep-voiced, sexily suited Rosalind. She and Dominic West, who is very good as a rugged, damaged Orlando, occasionally rise above their surroundings and communicate the aching need and the sexual ambiguity in this odd courtship. But to soar properly they would need to be in an As You Like It of genuine daring rather than presumption.