Cameron Diaz found it "torture" to be 20 years old.

The 39-year-old actress - who turns 40 on August 30 - isn't bothered about getting older and she works out "everyday" to stay in shape, but the blonde beauty is glad that she will never have to be in her 20s again.

"I don't worry about age. I never have. I couldn't wait to get into my 30s when I was in my 20s. I don't want to go back to being 20, it was torture. When I'm not working I train everyday I can. I like weights. It's important for women to have strong muscles - that's what carries you."

Cameron - who plays pregnant Jules in her latest movie, What To Expect When You're Expecting - admits she disliked it when she recently got her hair chopped, but she has now grown to love her shorter locks: "I said, 'Yeah, I want to go shorter,' and she went a bit shorter than I'd anticipated! I was like, 'The back of my neck's exposed!' Then I went, 'I like this haircut. Look how cute it is!'"