Keira Knightley pretends to be Britney Spears

London: Actress Keira Knightley has revealed she is often mistaken for Britney Spears and plays along and pretends to be the singer.The 29-year-old `Begin Again` star has reportedly signed autographs pretending to be Spears.

"It has happened to me three times in LA. I was quite excited by that and definitely signed and had a picture," she said. The British beauty said she has very little in common with the singer, 32, as she hates singing in public. "I like singing if I`m in my own in the shower or if I am really drunk, but I`m not a big fan of singing in front of people, which I didn`t realise until I said yes to the movie and found myself singing in front of rather a lot of people," Knightley said. The actress said she is also often mistaken for other celebrities, including Kate Winslet and Natalie Portman, in Los Angeles.