Slim Down Like The Stars

Too busy to hit the gym? Stars like Jessica Simpson, Lady Gaga and Alicia Keys have found a quick and easy way to stay fit, thanks to Harley Pasternak. The trainer created the following 45-minute circuit training session to sculpt these super-busy A-listers. It gets results, can be done anywhere (backstage or in a hotel room) and fits into the most hectic of schedules.

CHECK OUT THE GALLERY TO SEE HOW HARLEY PASTERNAK WHIPS HOLLYWOOD'S HOTTEST SINGERS INTO SHAPE!