Dirty Grandpa In Theaters January 22, 2016. Starring Robert De Niro, Zac Efron, Aubrey Plaza, Zoey Deutch, Julianne Hough, Jason Mantzoukas, Danny Glover, Adam Pally, and Dermot Mulroney. , DirtyGrandpa, YouDontKnowDick Jason Kelly Zac Efron is one week away from marrying his bosss ubercontrolling daughter, putting him on the fast track for a partnership at the law firm. Howev