Cast of 17 Again

Zac Efron portrays the younger version of Mike O'Donnell, a man who magically transforms back to his 17-year-old self.

Leslie Mann plays Scarlett O'Donnell, the estranged wife of Mike O'Donnell who he tries to reconnect with after his transformation.

Thomas Lennon takes on the role of Ned Gold, the geeky and wealthy best friend of Mike O'Donnell.

Michelle Trachtenberg portrays Maggie O'Donnell, the teenage daughter of Mike O'Donnell.

Sterling Knight plays Alex O'Donnell, the teenage son of Mike O'Donnell who struggles with self-confidence issues.

Matthew Perry represents the adult Mike O'Donnell, who gets the opportunity to revisit his youth after being transformed into his 17-year-old body.

Tyler Steelman appears as the teenage Ned Gold, who is depicted as Mike O'Donnell's high school best friend.

Allison Miller plays the teenage version of Scarlett, Mike O'Donnell's high school sweetheart and future wife.

Adam Gregory portrays Dom, a high school basketball star and rival to the younger Mike O'Donnell.

Hunter Parrish takes on the role of Stan, a high school bully who causes trouble for the younger Mike O'Donnell.

Mario Cassem plays Samir, one of Ned Gold's geeky friends in high school.

Kat Graham portrays Jamie, a high school student and friend of Ned Gold.