The actress also reveals the best beauty advice she's ever received.
Keira Knightley says her acting career ultimately took a toll on her hair.
The two-time Oscar nominee tells InStyle UK that she started taking a different approach when altering her image for a role. "I have dyed my hair virtually every color imaginable for different films," she admits. "It got so bad that my hair literally began to fall out of my head! So for the past five years I’ve used wigs, which is the greatest thing that’s ever happened to my hair."
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Given her confession, we're guessing Knightley's blonde bob in The Imitation Game was actually a wig, as well as her short brunette style in Everest.
Since giving birth to daughter Edie last summer, the 31-year-old actress says that her beauty regimen has become a bit more relaxed and does find that her hair sometimes suffers. "I have naturally crazy, curly hair, and since I’ve had the baby it’s become 10 times thicker," she explains. "So now I’ve been finding quite a lot of dreadlocks."
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She adds, "My new approach is, 'Do what you can remember, and don’t worry about it too much.'"
Knightley also reveals the best beauty advice she's ever received. "I was told very early on that if a make-up artist tries to take your eyebrows off," she quips, "That means he or she is absolute s**t."
ET was with Knightley in 2005 when she appeared to have dyed her hair for Pride & Prejudice. Here's a look back at her renowned role: