Actress Keira Knightley. Photo by Vianney Le Caer/Invision/AP

Keira Knightley had to change her career plan and take a step out of the spotlight to stop herself from "giving up".

The 33-year-old actress revealed that she decided to step back from big studio blockbusters because of her mental health, and she feels it was better to make different professional choices rather than find a new job.

She told Stylist magazine: "It was the only decision. It was either that or give up, so I thought, 'OK, I'm going to try and get [my career] to where I want it and see if I can make something sustainable and if I don't then I'll have to do something else.'

"We are all trying to make our life the best we can, and for me it's not going to be the best it can be if I'm doing massive studio films. The press around them is way too much for me. That's not the lifestyle I want."

Last month, Keira - who has been starring in movies since she was a teenager" - said that whilst she's developed tougher skin against her critics now, she wasn't so strong when she first started getting backlash for her roles.

Asked how she copes with negativity, she recently said: "I remember that perfection doesn't exist. But I struggled at first. I'd been a straight-A student, I'd never had a detention, I was on set every day on time, I'd done my research, I knew my words ... I had that desperation for the 'A' the entire time. And I suddenly went, 'Oh f**k, it's crumbling. I don't know what to do.'"

And whilst she tried to not let the negativity bring her down, her young age meant she was more impressionable, and found it difficult to "please everybody" - especially when everyone seemed to want her to be something different.

Commenting on how the comments got to her, the 'Anna Karenina' actress added: "It can't not. At that age all you want to do is fit in. But when you're the girl who's been taught to be perfect, all you want to do is please everybody. But I couldn't be thinner and fatter at the same time."