Lily Aldrin is a fictional character in the CBS television series How I Met Your Mother. Lily is portrayed by American actress Alyson Hannigan. She is married to Marshall Eriksen and is best friends with Ted Mosby, Robin Scherbatsky and Barney Stinson. Lily is a kindergarten teacher and an amateur painter. In the eighth season, she gets a job as an art consultant. She is the only member of the original main cast, who has not appeared in every episode because Alyson Hannigan took leave after giving birth to her first child.

Theodore Evelyn Mosby is a fictional character and the protagonist in the American sitcom How I Met Your Mother, portrayed by Josh Radnor. He serves as the show's narrator from the future, voiced by Bob Saget, as he tells his children the "long version" of how he met their mother.