Keira Knightley " too shy to talk to her fans".

Keira Knightley has revealed that she intentionally dresses down while out in public because she's too shy to talk to her fans.

The star also admitted that she struggles with fame because she is naturally 'very shy' and feels uncomfortable when people stop her in the street.

Knightley always wears her scruffiest clothes when out and about in a bid to go unnoticed, and avoids showbiz parties to maintain her low profile, but the 25-year-old fears her tactics aren''t working.

"I think it (fame) broke something in me. I was told very early on that if I didn''t go out to openings and parties and events I would be left alone. I didn''t, and they still didn''t leave me alone," the Daily Star quoted Knightly as telling Vogue magazine.

"I knew it was part of the deal in the life I had signed up to, but the fear of it has never left me. I''m still not good at being recognized. I wear scruffy clothes and hats and keep my head well down. I''m sure people must think I''m a complete b**ch, but I''m just very shy," she added.

Keira Knightley 'almost quit Hollywood at 22'

Keira Knightley has revealed that she almost gave up acting three years ago because she "wasn't enjoying" her Hollywood career.

The actress shot to fame as a teenager in 2002 soccer movie 'Bend It Like Beckham' and she has enjoyed a string of successful films since.

The 'Pirates of the Caribbean' star admits she decided to turn her back on acting altogether at the age of 22, because she had worked nonstop since she was 16 years old.

But after a hiatus, Knightley realised her passion for her job.

"I think I intended not to work again. I wasn't enjoying what I was doing and I felt terribly guilty about that," Contactmusic quoted her as telling Vogue magazine.

"I remember hating the idea that I was in a privileged position and couldn't see the point of any of it.

"I had worked solidly since I was 16, till 22, and I had not been on holiday in all of that time. I didn't know if I was going to go back to acting at all. I think for a long time I thought I wouldn't," she said.