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 (2005) and the crime drama Alpha Dog (2006). She also had a recurring role on the UPN television series Veronica Mars (2004–2006). Between 2006 and 2011, Seyfried starred on the HBO drama series Big Love. She also starred in the musical feature film Mamma Mia! (2008) and reprised her role in the sequel, Mamma Mia! Here We Go Again (2018).