After Molière Comedy Theatre Keira Knightley may be one of 21st century cinema's revered objects, but on stage she proves little better than adequate.

Her arrival on the West End in an interesting (but intellectually disingenuous) treatment of Molière's Le Misanthrope is, well, on the dull side.

She has all the charisma of a serviceable goldfish.

Knightley has a flawless face, but it does not move about much. In a film actress this is often an advantage, but on stage it is a snag. It's like giving a carpenter a blunt chisel.

On film you can sit like a cat and allow the director to do much of the mood work. The occasional word here and there, a longing glance to camera, and, hey presto, you're an international celeb.

On stage you have to project, not just the voice (here a tuneless American accent) but also the whole being, physically, emotionally.

This is particularly true if you are playing some supposedly ravishing creature who manages to be the centre of attention. Knightley's character, Jennifer, is meant to be a movie star, a magnet not just for the lusts of assorted, grisly hangers-on, but also of a mercurial playwright called Alceste (Damian Lewis).

Alas, the character as portrayed by Knightley is little beyond an elegant mannequin. The only time she starts to soar, oddly, is when she is dressed in a 17th-century French costume.

Paradox

Would Alceste, so enraged by modern art and politics, really give such a dull dolly more than a glance? This production bears little relation to Molière, even though the long dead Frenchman appears on the credits. It is really the work of Martin Crimp.

Who he? Well, here's the paradox. Chum Crimp is one of the most laughably fashionable and, in my view, over-promoted playwrights of luvvie London. His work with trendy director Katie Mitchell is absurdly garlanded by some of the impressionable fools of the British state-subsidised theatre.

Furthermore, here he is riding into town on the back of a transatlantic star such as Knightley, who is better known simply for being famous than she is for her thespian artistry. And yet Crimp's verse play, often excitingly angry, makes repeated attacks on celebrity and flattery and falseness, and the whole gruesome world of the fashion-arts darlings.

It does not help Knightley that she is up with an accomplished cast including Damian Lewis, Dominic Rowan, Nicholas Le Prevost and Tim McMullan.

Tara FitzGerald is also on the premises, playing the ex-best friend of Knightley's Jennifer. Ah, FitzGerald. Now there is a proper stage actress, with a mouth that can go from winsome to goofy in one flash of a smile. She only has to place a hand on hip to have buckets more allure than crystallimbed Knightley.

Some may find Crimp's verses a little Rupert Bearish, in places even like William McGonagall (he rhymes ‘Jackson Pollocks' with ‘b******s') but I quite liked the discipline of the form.

More irritating was a certain pretentiousness, not least in the bad language. I counted the "F" word 21 times. If Alceste truly yearns to be an iconoclast might he not find it more daring to abjure such grottiness?

Casting the underpowered Knightley in this anti-fashion play is merely indicative of Crimp's lack of self-knowledge.