Although the “American Pie” movies were quite successful, Alyson’s big breakthrough was still to come. Of course, she had already had garnered some fame as “Willow” on “Buffy The Vampire Slayer”, but when she was cast as “Lily Aldrin” in the CBS sitcom “How I Met Your Mother”, she became known all around the world. Alyson Hannigan is married to fellow actor Alexis Denisof and they have two daughters.