Hilary Erhard Duff (born September 28, 1987) is an American actress and pop music singer. After gaining prominence in the television show Lizzie McGuire, she has since gone onto a film career, with roles in mainstream pictures such as Cheaper by the Dozen, A Cinderella Story and independent films such as Material Girls and The Perfect Man. Duff has also launched a successful music career that has yielded two number one albums in the U.S.

Hilary Duff was born in Houston, Texas as the second child of Robert Erhard Duff, owner of a chain of convenience stores, and his wife Susan Colleen Cobb, a homemaker. Duff's middle name of "Erhard" was the maiden name of her part German American paternal grandmother, Mary Erhard; Duff also has German ancestry on the part of her maternal grandmother, Amy Beulah Schlemmer. After Duff's mother encouraged her to take an acting class alongside her older sister, Haylie Duff, both girls won parts in various local theatre productions. At the age of six, the Duffs participated in the ballet The Nutcracker Suite with Columbus Ballet Met in San Antonio. The siblings became more and more enthusiastic about the idea of acting professionally, and they eventually relocated to California with their mother. Bob Duff stayed at the family home in Houston to maintain their business. Through years of auditions and meetings, both sisters managed to clinch appearances in several television commercials.

Hilary Ann Duff was born on September 28th, 1987, in Houston, Texas, to Bob Duff and Susan Duff. When Hilary was six, she had been traveling in the Cechetti Ballet with her sister Haylie Duff but decided she wanted to fulfill her dream of acting. Her first part was in the mini-series True Women (1997) (TV), but her first starring role was as Ellie in The Soul Collector (1999/I) (TV), for which she won a Best Performance in a TV Movie or Pilot (Supporting Young Actress) Young Artist Award. Hilary also starred in Casper Meets Wendy (1998) (TV) in 1998, in which she played the young witch Wendy.

Success came again as she took the role of the starring title character Lizzie McGuire in the #1 hit Disney Channel series "Lizzie McGuire" (2001). "Lizzie" was extremely successful and spawned The Lizzie McGuire Movie (2003). In 2002, she made the Disney Channel movie Cadet Kelly (2002) (TV). Hilary continues her upward spiral, guest-starring on TV shows, filming movies, recording albums, and doing television concerts