Keira Knightley had a "mental breakdown" when she was 22.

Keira Knightley

Keira Knightley

The 'Pride and Prejudice' actress took a year out from her career and was diagnosed with post-traumatic stress disorder (PTSD) after struggling to cope with fame and the attention of being a global star but found therapy helpful.

She said: "I did have a mental breakdown at 22, so I did take a year off there and was diagnosed with post-traumatic stress disorder because of all that stuff.

"I went deep into therapy and all of that, and [a therapist] said, 'It's amazing -- I normally come in here and have people that think people are talking about them and they think that they're being followed, but actually they're not. You're the first person that actually that is happening to!' "

The 33-year-old star wanted to skip the 2008 BAFTA Awards, where she was nominated for the Actress in a Leading Role accolade for her role in 'Atonement', because of the "major panic attacks" she was gripped with but underwent hypnotherapy to get her through as she didn't want to be subject to a backlash for snubbing the ceremony.

She told The Hollywood Reporter's Awards Chatter podcast: "I actually did hypnotherapy so that I could stand on the red carpet at the BAFTAs and not have a panic attack.

"The hypnotherapy worked because I did stand there and I didn't have a panic attack."

The 'Colette' actress - who has three-year-old daughter Edie with husband James Righton - admitted the period following her early movie success such as 'Bend it Like Beckham' and 'Pirates of the Caribbean' was "insane" because although she was doing very well in her career, she only paid attention to the negative comments.

She said: "That run of films was completely insane.

"It's amazing looking back at it from the outside -- you're like, 'Whoa, that was hit after hit after hit!' But, from the inside, all you're hearing is the criticism, really.

"And, also, I was aware that I didn't know what I was doing, you know? I didn't know my trade, I didn't know my craft. I knew that there was something that worked sometimes, but I didn't know how to capture that.

"It was still very confusing, because you're getting all these nominations for all of these things, but press-wise, when I'm going into interviews, people are still saying, 'Everybody thinks you're s**t,' or focusing on your looks, or focusing on what's wrong with you.

"And, again, I was [20] you can only hear the negative stuff."