She began modeling when she was eleven, and acted in high school productions as well as taking singing lessons. She landed a recurring role in the long-running soap opera As the World Turns (1956) when she was just age 15.
More soap work followed as she completed her schooling and had already secured a place at Fordham University when she was offered a role in the Tina Fey-penned teen comedy Mean Girls (2004). She deferred her university education to complete the film. More television work followed, raising her profile across America, while her appearances in Mamma Mia! (2008) and Red Riding Hood (2011) helped establish her international fame.