Amanda Michelle Seyfried (born December 3, 1985) is an American actress, singer-songwriter and former child model. She began her career as a child model when she was 11 and when she was 15 she began her career as an actress; starting off with uncredited roles and going on to have a recurring roles on As The World Turns and All My Children, which expanded into her successful television and film career.In 2004, Seyfried made her film debut in Mean Girls playing Karen Smith, the ditsiest of the so called 'Plastics'. She then went on to other films including Nine Lives (2005) and Alpha Dog (2006). In 2006, she landed a lead role on HBO's popular television series Big Love. After that, Seyfried appeared as Sophie Sheridan in the 2008 musical feature film Mamma Mia!. Other recent notable appearances include lead roles in Jennifer's Body and Chloe in 2009, and one of the two lead roles in Dear John the following year.