Alyson Hannigan is an American actress best known for her roles in popular television series. She gained fame for portraying Willow Rosenberg on the hit show Buffy the Vampire Slayer and later starred as Lily Aldrin in the sitcom How I Met Your Mother. Her performances have earned her a dedicated fan base and critical acclaim. In addition to her television work, Hannigan has appeared in several films, including the American Pie series, where she played the memorable character Michelle Flaherty. Born on March 24, 1974, in Washington, D.C., she began her acting career at a young age and has continued to work in the entertainment industry.