In an interview in the latest issue of Allure magazine, the Atonement star also stated that she was insecure about the way she looks.
Knightley told the magazine: "I hate red-carpet events; I absolutely hate them. I don't like the fact that people write, 'Oh, you look like crap' in print. Or 'I don't like your arms!'"
Speaking about her self image, the 22-year-old star said: "I'm not Wonder Woman. I have self-esteem problems. Everybody does. You know, skinny people are allowed to feel **** about themselves."
Knightley, who has sued newspapers over anorexia claims, also said that she wasn't concerned about how much she weighs.
"I haven't got a clue about how much I weigh. I do not own any scales. And I have noticed it creates an anger in people who are not skinny.
People like to blame their insecurities on other people."
In the interview the actress, who was one of the shining stars at the recent Venice film festival, added that she preferred to play strong characters in films.
Knightley said the majority of female roles seen on the big screen were "overly sentimental".
