Keira Knightley is not scared by sex scenes.

The 'Never Let Me Go' star believes getting nude for a film role is not a big deal because everyone on set is often "respectful" and she always discusses what she is comfortable with beforehand.

She said: It's a consensual thing. You say what you're comfortable with and everybody's incredibly respectful."

However, the 25-year-old actress was not so comfortable with auditioning as a child because she believed everyone thought she was "s**t".

She told The Daily Telegraph newspaper: "Some kids did karate, I went to auditions. They were humiliating. You walk in a room and they obviously think you're s**t.

"So you walk again. I mean the rejection level of anyone who does anything like that. It is quite a savage process."

Recently Keira admitted she had considered retiring from acting until the opportunity to work with Carey Mulligan on drama 'Never Let Me Go' came up.

She said: "'I didn't know if I was going to go back to acting at all. I think for a long time I thought I wouldn't. I think I intended not to work again.

"Carey's a very good friend of mine and I felt if I was to start making films again, she was someone who would watch my back."