Sasha Pieterse Sheaffer (; born February 17, 1996) is an American actress and singer. She is known for portraying Alison DiLaurentis in the Freeform series Pretty Little Liars (2010–2017), and its spin-off Pretty Little Liars: The Perfectionists (2019), for which she received global stardom and critical acclaim. After early recognition for her roles as Buffy Davis in Family Affair (2002-2003) and as Marissa Electricidad / Ice Princess in the film The Adventures of Sharkboy and Lavagirl (2005), Pieterse played minor roles in various other films and series. She later rose to prominence with her role in Pretty Little Liars. Upon the success of Pretty Little Liars, Pieterse starred in films such as Disney Channel's Geek Charming (2011), teen comedy G.B.F (2013), indie film Burning Bodhi (2015), drama films Coin Heist (2017) & The Honor List (2018), and a psychological thriller film The Image of You (2024). Pieterse has participated in the 25th season of Dancing with the Stars (2017). In addition to acting, Pieterse has ventured into music and modeling. She served as a judge in one episode of shows Beat Bobby Flay and Sugar Rush Christmas (both 2020).