Atonement, an adaptation of the best-selling Ian McEwan novel, is widely tipped to be one of the biggest films of 2007 and marks the transformation of Keira Knightley from teen actress to leading lady

To coincide with the film's release, we spoke to Keira, who stars alongside James McAvoy, Brenda Belthyn and Vanessa Redgrave among others, about how she prepared for the film, her views on celebrity culture and the role her parents have played in her personal and professional life.

The director (Joe Wright) said he wanted you for this role because he thought you were 'ready for it'. What do you think about that? Do you sometimes get scripts that make you think 'I can't do that, I'm not ready'?

Keira Knightley: Every single script I get, I pretty much think, 'I can't do that.' I think it's going to be a challenge or that I might just fall flat on my face but that I might as well give it a go. I think that's all you can do.

He also said he wanted you as more of a sexual character because you've only tended to play girls before. Did you talk to him about that and do you agree?

Keira Knightley: Yes, we did talk about it but not that much. I'd only really played girls before because I was one! I mean, I was 16 in Bend it Like Beckham, 17 when I did Pirates of the Caribbean and I was probably playing appropriate roles for my age. Not that I feel particularly grown-up or womanly or anything like that now, but I certainly wanted to creatively explore a woman who is much more mature and sure of herself.

Is it a case of you not being confident in your work?

Keira Knightley: I have much more confidence in my work than I did have. I'm incredibly self-critical and I'm not particularly looking to get to a place where I've got total confidence. I don't particularly like watching actors on screen who are confident in their own ability. I want to see actors who are pushing themselves. I want to see actors who are discovering new things, who are learning new things and portraying emotions in different ways. So I don't particularly think it is a profession where being comfortable and confident really helps.

Are you interested by the period this film is set in and the different style of acting that was required?

Keira Knightley: Yes, one of the things I got really excited about was doing it in that very 1940's, 1930's style. It's a style of film acting that's pretty much gone really.

It's interesting that your mother is a writer. What did she say when you said you were going to do a film based on an Ian McEwan novel?

Keira Knightley: I think she said, 'Oh that's a good book.' She'd actually given it to me when it first came out. I can't remember when it was but it was one of those things that had been lying around in my house and I never got around to reading it. I actually read the script before I read the book and cried and thought that if the script could move me like that then it must be rather good. Then I read the book and it's an extraordinary piece of work, it really is. As an actress, it's a bit of a gift really because the characters are mapped out so beautifully. I didn't have to come up with anything. It was all already there.

Do you enjoy this kind of film more than, for instance, Pirates of the Caribbean?

Keira Knightley: Pirates was an amazing experience but it is what it is. It's a glass of champagne, it's a fun ride. It's a family movie that's about action. Elizabeth Swann is an action figure really. She fights monsters and kids love it. That's lovely but as far as being an actress goes, if you're looking for a little bit of intellectual stimulation in work then it's really lovely to do something based on such a beautiful book like Atonement where you can really just dive into it and explore. It's wonderful to do films that are just pure entertainment and there is a very valid place for that, but it was a wonderful antidote to do something like Atonement after it.

You have worked a lot over the last few years. Do you have time for a personal life?

Keira Knightley: I do but I like to work hard. I like to be pushed as much as possible. I was really lucky in the early part of this year as I didn't take a film for the first six months so I wasn't away from home, which was really important. A big part of the job is travel and as much as I love it, it's difficult to spend time away from your family so it was really important to take the six months and just stay in London and try and get normality there. I am trying to work a little bit more in London again for family reasons.

What do you like to do with your free time?

Keira Knightley: Normal stuff. I just love being home and making your own tea and having a toaster and things like that. It's being able to cook for yourself instead of having to eat in a restaurant. It's all those things. It's buying food from your local market and going to the cinema. Just the normal things that you don't get to do when you're sitting in a hotel room on your own having room service.

Is it more difficult to do normal, everyday things now?

Keira Knightley: Well, yes. I'm looked at a lot more but I think it would be horrendous if you just stopped going out because of that. I couldn't imagine doing that. I wouldn't want to hire somebody to go to do things for me. I mean, can you imagine (laughs)? I think you've got to do day-to-day things. You have to go, 'Okay well deal with it. It's fine,' and carry on.

Is it easy to escape the celebrity culture and people watching you?

Keira Knightley: The act of being watched is very strange. It's a sort of form of living madness really, because you're walking down the street and somebody is following you and that person is looking at you and you think your name is being whispered. Normally, that would mean that you have a psychological problem but in my case it's reality, and very strange. I love my job and I love acting but I would absolutely love it if I could be completely anonymous and just walk around. I think anybody can understand that. The reality is that I'm not going to get that so you just have to weigh it up and say 'I love what I do so put up with it and when you can't put up with it give it up.'

Are your parents proud of you?

Keira Knightley: I hope so. They haven't said that they're not. They're incredibly honest, which sometimes isn't necessarily what you want, but I really value them for that. They're incredibly supportive, they obviously see a reality to the business which isn't what is projected so it's great to be able to talk to them.

What do you make of people like Paris Hilton and Lindsay Lohan - these people who are always on magazine covers for no apparent reason?

Keira Knightley: I don't think they're part of my job (laughs). I think they can definitely answer that question better than me. When I do magazine shoots it's always to sell a film and it is always very clearly for that. I don't really read magazines that are about celebrity culture. It's not what interests me.

What about celebrity culture in general?

Keira Knightley: I don't particularly like it. It's not anything that interests me. I don't see the positives in it. My mum always told me that gossip was not a good thing so I don't participate in it.