Amanda Michelle Seyfried is an American actress, model, and singer-songwriter. She began her career as a model when she was 11 and her acting career at 15 with recurring parts on the soap operas As the World Turns and All My Children.In 2004, Seyfried made her film debut in the teen comedy Mean Girls. Her subsequent supporting roles were in independent films, such as the drama Nine Lives and the crime drama Alpha Dog . She also had a recurring role on the UPN television series Veronica Mars . Between 2006 and 2011, Seyfried starred on the HBO drama series Big Love. She also starred in the musical feature film Mamma Mia! and reprised her role in the sequel, Mamma Mia! Here We Go Again .Seyfried had lead roles in the black comedy horror Jennifer's Body , the erotic thriller Chloe , the romantic war drama Dear John , and the romantic drama Letters to Juliet .