"I wanted to vomit, which I was told was a very natural feeling."
So said Keira Knightley about first-night nerves last week ahead of her professional stage debut in a revival of Moliere's The Misanthrope.
In an interview in The Times, the star of Atonement and Pirates of the Caribbean admitted she "freaked out" when she was set an acting exercise by the play's director Thea Sharrock.
Knightley is the latest in a long line of Hollywood actors to swap movie glamour for the West End theatre - among them Nicole Kidman, Kevin Spacey and Harry Potter star Daniel Radcliffe.
Martin Crimp's version of The Misanthrope transports the action from 17th Century Paris to modern-day London, where Knightley plays an American movie star.
As previews began this weekend, we asked some well-known actors to share their wisdom on how easy - or terrifying - it can be to make the transition from screen to stage.