Keira Knightley says filming 'The Edge of Love' was "frightening"

Keira Knightley says shooting her new movie, The Edge of Love, was the most frightening experience of her life.

The British actress -- who plays Vera Philips, the lover of Welsh poet Dylan Thomas, in the movie -- admits she found the role incredibly tough.

She said: "I did some lessons with a voice coach because I can't sing. It was live. There were 100 extras and the director John Maybury was like, 'Now you're going to sing.'

"I've never been so frightened in my entire life. I never want to do it again. I don't want to be a rock star. "

In the film, which was written by Keira's mother Sharman Macdonald, the 23-year-old sings 'Blue Tahitian Moon', as well as renditions of 'Maybe It's Because I Love You Too Much' and 'Drifting And Dreaming'.

The film, expected to be in theaters mid-2008, also stars Sienna Miller, Cillian Murphy and Matthew Rhys.