ASHTON'S NEW JEANS: Ashton Kutcher is going back to his roots — and replacing Sienna Miller along the way. After getting his start as a Calvin Klein model, Kutcher has now been tapped as the face of Madrid-based denim brand Pepe Jeans London through fall. The actor will make his debut for Pepe in the brand's spring campaign, which was shot by David Sims in New York, and styled by Joe McKenna. Kutcher replaces Miller as the face of the brand, and he will share the spring campaign with model Daria Werbowy, who is contracted to Pepe for one season only.