Keira Knightley woke up on Friday morning to find London dusted with snow and a stack of praise on her doorstep. The British star, now Hollywood's second-highest-earning woman, had made her West End stage debut the previous night in an updated version of Moliere's The Misanthrope. She plays Jennifer, an ambitious American actress, who proves an Achilles' heel for the drama's central character Alceste, now an embittered playwright.
In Damian Lewis's biting performance, he rails against mankind, longing to live in a disinfected white box he hates human nature so much. But when faced with Jennifer's beauty and allure, he goes all soppy, excusing her flirtatious behaviour with other men by saying: "She's young and beautiful." In Knightley's performance she is indeed that. As thin as a coat hanger, she looks gorgeous, with a stage presence that much more experienced actresseses would envy. But it is her eyes that really have it. As Jennifer, she is required to run a gamut of emotions, from the passionate, to the wounded, and ultimately to the lost.
Knightley registers all of that not vocally, but with a kind of wide-eyed expressiveness, letting feelings chase across her face. It seems to me that this is a film actress's ability, and to see it used so effectively on stage is very powerful. At the end she stands alone, spotlighted in the midst of a 17th-century costume party, isolated in the trivial world she has chosen, her eyes vacant. It is a haunting, ambiguous image.
Before she took to the stage, Knightley confessed to the BBC that she feared she would be "roasted alive by the critics", adding: "I'm not coming into it with any great expectations of coming away with great reviews. If my best isn't good enough, then so be it." Some critics - who are heavily satirised in the course of Martin Crimp's updated version of the play, being described as "dead white males" - have lived up to her expectations. Writing in the Daily Mail, Quentin Letts claimed she "has all the charisma of a serviceable goldfish". But most of his colleagues were generally kinder. In The Daily Telegraph, Charles Spencer said: "After a hesitant start she gets better and better in the admittedly not especially stretching role," adding: "She makes you realise why Alceste is so obsessed with the movie star-There is a mystery to Knightley's allure, and an endearing streak of mischief in her portrayal."
Michael Billington, in The Guardian, also liked what he saw. "Knightley brings to the role fine, sculpted features, palpable intelligence and a nice mix of faux-innocence and flirtiness." And in The Independent, Paul Taylor was even more complimentary: "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." There is a strange double irony in casting an inexperienced film star in a play that holds up the world of celebrity to coruscating attack. But the greatest compliment that can be paid to Knightley is that she holds her own as part of an ensemble of actors in Thea Sharrock's sharp and enjoyable production who are all on very fine form - most notably Lewis, who brings to Alceste the perfect mixture of righteousness and ridiculousness.
Celebrity casting, it is true, has become a modish idea in the London theatre. Plays are generally - and surprisingly - thriving in the West End, but there can be no doubt that the presence in a starring role of someone who is widely known brings in audiences and attracts attention. Tickets for The Misanthrope flew out of the box office at record speed once Knightley's involvement had been announced.
In recession, and in a highly competitive market, those are qualities that are likely to appeal to any shrewd producer. And in recent years, the trend has notched up far more successes than failures: Madonna may have flopped in Up For Grabs? (a satire on the greed of the art market unveiled in 2002), but Jude Law and David Tennant have both sold out shows as Hamlet - and delivered memorable performances.
Dominic West, an experienced stage actor given new gloss by his appearances in the television series The Wire, burnished a remarkable revival of Pedro Calderon de la Barca's Life's a Dream with his presence. Gillian Anderson, once best known for The X Files, was a powerful Nora in Ibsen's A Doll's House. What is encouraging about these forays is that the celebrity stars are lending their weight to plays that are not obviously box office. West's presence, for example, guaranteed an audience for a difficult, philosophical 1635 play from the Spanish Golden Age that is always on critical lists of masterpieces but rarely performed. It was magical and riveting to see. Equally, Law and Tennant made Shakespeare suddenly sexy, their very presence emphasising the idea that you don't have to study him, you can enjoy him too.
Now Knightley has joined that honourable tradition, encouraging a new generation of theatre-goers to discover the savage brilliance of Molière - and in the process keeping his plays and his reputation alive. Not a bad use of celebrity status.