By Leah Ornstein

Breaking Celebrity News Style & Beauty Editor

Amanda Seyfried will be steaming up the screen this Friday, starring alongside Justin Timberlake in the action thriller flick In Time. But while most actresses have to sweat their fannies off to get in shape for such a sultry and sexy role, the bombshell blonde didn’t have much work to do – and Shape magazine knows her secret.

Seyfried has been working with celebrity trainer Harley Pasternak for the last few years and follows his famous 5-Factor Program to stay in stellar shape.