Jennifer Hudson

Dropping from a size 16 to a size 6 looks great on actress-singer Jennifer Hudson. The new mom and Weight Watchers spokeswoman teamed up with celeb trainer Harley Pasternak, whose 5-factor workout plan combined with a low-calorie, healthy diet brought out the fittest Jennifer ever. The impetus for dropping her post-pregnancy pounds after the birth of her 10-month-old son David: playing Winnie Mandela in an upcoming biopic. "Whatever it takes to morph into a character I'll do it," Hudson recently told People. Learn more about Pasternak's workout regimen at FiveFactorWorkout.com.