Fitness fanatic Beyoncé

Beyoncé Knowles has revealed she has to work out five times a week to stay in shape.The singer-and-actress, who lost 13lbs in just ten days on a liquid-only diet for her new film 'Dreamgirls', admits she has to be very strict with herself to stay fit because she is naturally curvy.Beyonce, who is dating rap star Jaz-Z, said: "I workout five times a week. I get up in the morning at around 8.30. I eat my cereal and I let it digest, then I do cardio for half an hour, followed by free weights for about 45 minutes."Although her extreme eating regime produced the desired results, Beyoncé warned other women not to copy the diet.The stunning star - who survived on an unappetising blend of maple syrup mixed with water, lemon juice and cayenne pepper - said: "In 'Dreamgirls', my character starts at 16 and then 20 years pass. Normally they'd change your make-up or your clothes but I wanted to go the extra mile. My nutritionist suggested the only way to do that was the fast. As soon as it was over I gained the weight back. I would never recommend it to anyone unless you are doing a movie."