Get ready to see Robert De Niro [1] like you've never seen him before (very, very dirty) — and Zac Efron [2] like you have (shirtless [3]). In Dirty Grandpa, the two pair up as grandson Jason (Efron) and recently widowed grandpa Dick (De Niro) head to Daytona Beach, FL. Age is nothing but a number to Dick, who wants to get with pretty college girls like Aubrey Plaza and basically make strait-laced Jason's life a living hell. It's kind of like The Hangover meets Spring Breakers with a side of elderly person sex. The red-band trailer for Dirty Grandpa is now available too, with twice as much of De Niro being filthy, but there is a reward of a mostly nude Efron if you stick around. The movie comes out Jan. 22, so check out the red-band trailer now.

Watch the green-band trailer: