Alyson Hannigan 1989, her first regular role on a TV series came when she was cast in the short-lived ABC sitcom "Free Spirit". As a teenager, Hannigan babysat for the children of her future "How I Met Your Mother" costar, Bob Saget. In 1997, Hannigan was cast to play Willow Rosenberg, Buffy Summers' best friend, on the television series "Buffy the Vampire Slayer". The show became a success, and Hannigan gained recognition, subsequently appearing in several films aimed at teenaged audiences, including "American Pie" (1999), "Boys and Girls" (2000), "American Pie 2" (2001), and "American Wedding" (2003). She also had a guest
Buffy the Vampire Slayer (film) Buffy the Vampire Slayer (film) Buffy the Vampire Slayer is a 1992 American comedy horror film directed by Fran Rubel Kuzui and starring Kristy Swanson, Donald Sutherland, Paul Reubens, Rutger Hauer, Luke Perry, and Hilary Swank. It follows a Valley girl cheerleader named Buffy who learns that it is her fate to hunt vampires. It was a moderate success at the box office but received mixed reception from critics. The film was taken in a different direction from the one its writer Joss Whedon intended, and five years later, he created the darker and acclaimed TV series of the same