Amanda Michelle Seyfried ( SY-fred; born December 3, 1985) is an American actress and singer. Born and raised in Allentown, Pennsylvania, she began modeling at age eleven and ventured into acting at age 15 with recurring roles as Lucy Montgomery on the CBS soap opera As the World Turns (1999–2001) and Joni Stafford on the ABC soap opera All My Children (2003). Seyfried came to prominence following her feature film debut in the teen comedy Mean Girls (2004) and her recurring role as Lilly Kane on the CW/Hulu television series Veronica Mars (2004–2006) and Sarah Henrickson on the HBO drama series Big Love (2006–2011).

Seyfried has appeared in a number of films, including Mamma Mia! (2008) and its sequel Mamma Mia! Here We Go Again (2018), Jennifer's Body (2009), Dear John (2010), Letters to Juliet (2010), Red Riding Hood (2011), In Time (2011), Les Misérables (2012), A Million Ways to Die in the West (2014), Ted 2 (2015), and First Reformed (2017).

Seyfried received critical acclaim for her portrayal of Marion Davies in David Fincher's biopic Mank (2020), earning nominations for the Academy Award and Golden Globe Award for Best Supporting Actress. This acclaim continued for her starring role as Elizabeth Holmes in the drama miniseries The Dropout (2022) for which she earned nominations for the Primetime Emmy Award for Outstanding Limited or Anthology Series as a producer on the show and for her performance for the Primetime Emmy Award for Outstanding Lead Actress in a Limited or Anthology Series or Movie. Time magazine named her one of the 100 most influential people in the world in 2022.