Keira Knightley doesn't worry about the way she looks.

The 29-year-old actress is often hailed as one of the most iconic British beauties, with her chiseled cheekbones and famous pout, but the only time she dwells on her appearance is when it prevents her from landing film roles.

She admitted in an interview with France's Madame Figaro magazine: ''I never even think about beauty. Supposedly being pretty is a double-edged sword: your look gets you certain roles, but disqualifies you from others. That's the way the industry goes.''

And Keira - who is married to The Klaxons musician James Righton - claims she was such a tomboy when she was growing up that she never even wore a skirt or showed any interest in make-up until she was 14.

She recalled: ''I used to be a tomboy... I didn't even wear a dress or a skirt until I was 14. Then I started to experiment with make-up when as soon as I was allowed to, because it was fun to change your appearance when you're a teen.

''Later on, you want to be seductive for people in general and for boys sometimes too.''

The 'Atonement' actress is now the face of Chanel's Coco Mademoiselle fragrance, and while she enjoys the theatrics of putting on a show for the cameras, she insists she is simply playing a part.

Asked how one becomes like her, Keira laughed: ''Thanks to make-up, good lighting and couture gowns. I play a role and become the representation that people expect of me. But it's part of my job.

''Transforming yourself is also part of an actor's job. On the one hand, there's the public image of me, and on the other, a private person.''