By EW Staff
Updated December 04, 2007 at 05:00 AM EST

Michelle Trachtenberg (Buffy the Vampire Slayer) and Melora Hardin (The Office) have joined the cast of 17, the New Line teen comedy starring High School Musical star Zac Efron. Burr Steers (Igby Goes Down) is directing from a Jason Filardi (Bringing Down the House) script. The story is about a middle-age father who wakes up to find he’s 17 again and enrolls in the same school his children attend so he can get closer to them. Efron plays the teen version of the father while Matthew Perry has already been cast to play his adult counterpart. Leslie Mann has been cast to play Perry’s wife. Trachtenberg will play Efron/Perry’s daughter, who has a crush on the teen version of her own father. Hardin is the principal at the school. (Hollywood Reporter)