Haylie Katherine Duff is an American actress and singer. She is best known for her roles as Sandy Jameson in the television series 7th Heaven, Amy Sanders in Lizzie McGuire and Summer Wheatley in Napoleon Dynamite. An avid food blogger, Duff had her own cooking show, The Real Girl's Kitchen, in 2014. She is the older sister of Hilary Duff.

Lizzie McGuire is an American comedy television series created by Terri Minsky that premiered on Disney Channel on January 12, 2001. The series stars Hilary Duff as the titular character who learns to navigate the personal and social issues of her teenage years. Duff also voices an animated version of Lizzie that performs soliloquies to express the character's inner thoughts and emotions. The series also stars Lalaine, Adam Lamberg, Jake Thomas, Hallie Todd and Robert Carradine. The series concluded on February 14, 2004, after a total of 65 episodes were produced. A feature film based on the series, The Lizzie McGuire Movie, was released in 2003.