who played lily in how i met your mother
Alyson Hannigan Alyson Lee Hannigan (born March 24, 1974)[1] is an American actress. She is best known for her roles as Willow Rosenberg on the television series Buffy the Vampire Slayer (1997–2003), Lily Aldrin on the sitcom How I Met Your Mother (2005–2014), and Michelle Flaherty in the American Pie film series (1999–2012).[2]