View gallery Image Credit: Getty Images Zac Efron is best known for his breakout role as Troy Bolton in High School Musical, his chilling portrayal of Ted Bundy in Extremely Wicked, Shockingly Evil and Vile (2019), and his Netflix series Down to Earth with Zac Efron. But to his siblings-brother Dylan and younger half-siblings Olivia and Henry-he's simply "big bro." Zac and Dylan share the same parents, David Efron and Starla Baskett, while Olivia (born Dec. 26, 2019) and Henry are David's children from his second marriage.