Robert De Niro and Zac Efron want to party 'til they're pregnant! The two bro it the hell out in the new trailer for "Dirty Grandpa." De Niro is the titular patriarch, who goes on a road trip to Daytona Beach with his grandson (Efron) after the death of his wife. He's ready to cut loose and bag some hot babes. Efron is hesitant at first - he's engaged to be married - but soon finds himself accidentally smoking crack and playing flip cup next to gramps. Watch BuzzFeed's exclusive premiere of the Dirty Grandpa trail...

Watch BuzzFeed's exclusive premiere of the Dirty Grandpa trailer starring Zac Efron and Robert De Niro! bzfd.it/1NAPl7c

Posted by BuzzFeed Celeb on Wednesday, October 28, 2015 "Dirty Grandpa" looks like it fits right into Efron's oeuvre, while De Niro seems to be enjoying himself as the old dude opposite millennials (a la "The Intern"). There's nothing groundbreaking here, but it looks like the kind of raunchy fun that made "Neighbors" a hit. "Dirty Grandpa" opens in theaters January 22. Want more stuff like this? Like us on Facebook.