Keira Knightley admits she once had "no life outside of acting".

The British actress struggled with her fame after appearing in movies such as Bend It Like Beckham and the Pirates Of The Caribbean franchise. The 27-year-old has revealed the downside to being so successful in the film industry was missing out on experiences while she was growing up.

"I literally had no life outside of acting, and I just wanted to go off and not be 'on' all the time, not be photographed..." Keira admitted to Vogue magazine. "I once went to the Glastonbury music festival and was completely surrounded by packs of paparazzi the entire time, so I ended up sitting in a trailer, unable to go out."

The star is currently promoting Anna Karenina, in which she plays the title role. Keira was drawn to the movie because she felt the character rang true to how people really are.

"She is both a villain and a heroine. She can be incredibly vain and manipulative. She is somebody who breaks her own moral code, and yet the shame and disgust she lives with because of that make her fascinating," Keira explained.

"I think a lot of people want to play heroic characters, and that's it but I don't find that very compelling. It's far more interesting to think about characters whose actions don't always make sense. The fact is, the opposite is always alive in every decision. And if you look at your own life, and the way you've behaved and thought, it won't always make sense either."