British actress Keira Knightley refuses to set foot in a gym - and puts her slim figure down to a combination of a grueling work schedule and her love of dancing to songs on the radio. The Atonement star admits she could never subject herself to a punishing work out regime favoured by many stars in a bid to keep fit and slim. The 22-year-old has attempted to get into the spirit and take exercise classes - but the experience put her off for life. She says, "I really like the idea of yoga but I can't do it. It just pisses me off. If anybody tells me to relax then I just tend to tense up. That's why I'm not a yoga girl at all unfortunately. "And gym work is just so boring and repetitive. I'm not a gym person at all. The most exercise I get when I'm not working is when I turn up the radio."