Hilary Erhard Duff (born September 28, 1987) is an American actress, singer-songwriter, businesswoman, and author. Duff began her acting career at a young age, and was soon labeled a teen idol after playing the title character in the Disney Channel comedy series Lizzie McGuire (2001–2004) and the film based on the series, The Lizzie McGuire Movie (2003). Thereafter, she appeared in numerous mainstream films such as Cadet Kelly (2002), Agent Cody Banks (2003), Cheaper by the Dozen (2003), A Cinderella Story (2004), and Cheaper by the Dozen 2 (2005). In 2026, Time named her one of the 100 most influential people in the world. She also appeared in independent films playing a wider range of adult-themed roles, such as War, Inc. (2008), According to Greta (2009), Bloodworth (2011), and The Haunting of Sharon Tate (2019). Duff starred as Kelsey Peters in TV Land's longest-running original series Younger (2015–2021) which earned her award nominations, and produced and starred as Sophie Tompkins in the Emmy-winning Hulu sitcom How I Met Your Father (2022–2023). In 2002, Duff entered the music industry, and her debut studio album, the Christmas-themed Santa Claus Lane, was released that year through Walt Disney Records. Duff later signed with Hollywood Records and achieved greater success with her second album, Metamorphosis (2003), which topped the Billboard 200 chart and earned a 4× Platinum certification from the Recording Industry Association of America (RIAA). She also enjoyed significant commercial success with her subsequent albums, Hilary Duff (2004) and Dignity (2007), as well as the 2005 compilation Most Wanted which all went to be certified platinum and gold. Following a decrease in musical activity, Duff signed with RCA Records for her fifth album, Breathe In. Breathe Out. (2015), before transferring to Atlantic Records for her sixth album, Luck... or Something (2026). She has received media praise and has been noted as a blueprint for subsequent teen Disney Channel stars such as Miley Cyrus and Selena Gomez, and has sold an estimated 15 million records worldwide. Billboard ranked her at number 73 on their "Top 100 Women Artists of the 21st Century Chart" list. She appeared on Forbes' annual Celebrity 100 list from 2004 to 2007. In addition to music and acting, she has also co-authored a trilogy of novels, beginning with Elixir (2010), which topped The New York Times Best Seller list, and followed by the sequels Devoted (2011) and True (2013). Duff's success in the entertainment industry led her to venture into business with fashion and fragrance lines of her own, such as Stuff by Hilary Duff, Femme for DKNY, and With Love... Hilary Duff. She is the Chief Brand Director of Below 60°, a line of home fragrance products. She has also invested in a number of businesses, ranging from cosmetics to children's products.