Hilary Erhard Duff (born September 28, 1987) is an American actress, pop singer-songwriter and entrepreneur. After gaining fame for playing the title role in the television show Lizzie McGuire, Duff went on to have a film career; her most commercially successful movies include Cheaper by the Dozen (2003), The Lizzie McGuire Movie (2003), and A Cinderella Story (2004)..