Hilary Erhard Duff (born September 28, 1987) is an American actress and singer–songwriter. After working in local theater plays and television commercials in her childhood, Duff gained fame for playing the title role in the television series Lizzie McGuire. Duff subsequently ventured into feature films, with her most commercially successful movies being Cheaper by the Dozen, The Lizzie McGuire Movie, and A Cinderella Story.

Duff expanded her repertoire into pop music with the release of three RIAA-certified platinum albums and over thirteen million records sold worldwide as of February 2007. Her first studio album, Metamorphosis (2003), was certified triple platinum and she followed it up with two more platinum albums, Hilary Duff (2004) and Most Wanted (2005). Duff had a musical comeback with the release of her third studio album, Dignity (2007), which was certified gold in August 2007 and released two singles, "With Love", her biggest US single to date and "Stranger". In November 2008, she released another Greatest Hits compilation, Best of Hilary Duff with her third #1 on the Billboard Hot Dance Club Play single "Reach Out" .

Duff has also launched clothing lines including, "Stuff by Hilary Duff", and Femme for DKNY Jeans and two exclusive perfume collections with Elizabeth Arden. Duff and her mother were listed as producers for the movie Material Girls. Duff is credited as executive producer for the upcoming independent film Greta.