Zac Efron's 'Dirty Grandpa' Trailer Shows His Insane Six Pack - Watch Now!

Zac Efron shows off his ripped shirtless physique in the brand new trailer for his upcoming film Dirty Grandpa!

We’ve always known that the 28-year-old actor had an amazing six pack — but we’re still in awe!

The trailer debuted on BuzzFeed‘ Facebook page also features shirtless Robert de Niro, Julianne Hough, Zoey Deutch, Aubrey Plaza, and many more.

Here’s a synopsis: Right before his wedding, an uptight guy is tricked into driving his grandfather, a perverted former Army general, to Florida for spring break.

The movie is set to be released on January 22, 2016! Watch the trailer below…