Keira on stage: more than a pretty face - just

So, can Keira Knightley, movie star, hack it on the West End stage? The answer, according to the majority of London's theatre critics this morning, is yes, just. Only one - the Daily Mail's Quentin Letts - writes her off as a hopeless cause. "She has all the charisma of a serviceable goldfish," he writes. "Miss Knightley has a flawless face but it does not move about much."

The star of Attonement and the Pirates of the Caribbean made her stage debut at the Comedy Theatre last night in Moliere's The Misanthrope, updated by Martin Crimp from 17th century Paris to present-day London.

The 'misanthrope' is a grumpy English playwright - played by Damian Lewis - who, while railing against the triviality of contemporary culture, against all his better instincts falls for a beautiful and ambitious American film star, played by 24-year-old Knightley.

The most enthusiastic response so far comes from Paul Taylor in the Independent, who writes: "The critical knives were unsheathed and quivering. So it's a tonic to report that Knightley [turns] in a performance that is not only strikingly convincing but, at times, rather thrilling in its satiric aplomb.

"A poster-girl for natural thinness, she makes Olive Oyl look chunkier than Roseanne Barr. It's not just that she cuts a stunningly beautiful figure here; it's that she has real stage presence and knows how to use it."

Benedict Nightingale in the Times is impressed, but less so. "She catches the waywardness, occasionally the steel behind the velvety manner, the narcissistic love of attention, but not the authority to explain how she can dominate a gathering by more than beauty.

"Partly the reason is physical. She's so wispy she could fit into an umbrella stand. Partly it's a want of vox, partly a lack of the assurance that more time on stage may bring her."

This obsession with Knightley's thinness gripped Charles Spencer of the Daily Telegraph, too. "She is undoubtedly beautiful and the camera loves her," he writes, "but in the flesh she seems almost scarily skinny. When her lover slaps her on the cheek, you fear the blow will knock this waif-like figure to the floor. What's required, urgently, are a few Krispy Kreme doughnuts and a couple of McDonald's Quarterpounders with cheese."

As for her acting, he felt she got "better and better" after a hesitant start. "There is a mystery to Knightley's allure, and an endearing streak of mischief in her portrayal of the actress... This stinging, zinging play would be a hit without Knightley. With her, it becomes unmissable."

Michael Billington in the Guardian asks: "Can Keira Knightley cut it? Since she's playing a movie star in her 20s, one could say that she is not unduly stretched. But Knightley brings to the role fine, sculpted features, palpable intelligence and a nice mix of faux-innocence and flirtiness. Even if she doesn't always know what to do with her hands, she gives a perfectly creditable performance.

Last word to Letts at the Daily Mail: "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... Alas, the character as portrayed by Miss Knightley is little beyond an elegant mannequin."

Damian Lewis gets warm notices from all the critics for his role as the playwright Alceste, but we knew he could act anyway - and, with all due respect, he's not the reason the Comedy box office has been taking record advance bookings.