Sasha Pieterse-Sheaffer (/ˈpiːtərsə/; born February 17, 1996 ) is a South African-born American actress and singer-songwriter. She is known for her role as Alison DiLaurentis in the Freeform series Pretty Little Liars and its spin-off Pretty Little Liars: The Perfectionists. Upon the success of Pretty Little Liars, Pieterse earned a supporting role as Amy Loubalu in the 2011 Disney Channel film Geek Charming. In 2013, she starred in the teen comedy film G. B. F. . In 2017, Pieterse participated in the 25th season of Dancing with the Stars and finished in 10th place.