Zac Efron Flaunts Fit Abs in New 'Dirty Grandpa' Photo!

Zac Efron looks pretty hilarious in this new still from his new film Dirty Grandpa.

The 28-year-old hottie appears with Robert De Niro in the photo, which he shared on Instagram.

“It’s been a life long dream of mine to work with De Niro,” Zac captioned it. “Lo and behold, I spend most of the movie naked or in women’s clothing. And you know what…it was TOTALLY WORTH IT. I can’t wait for you to see @dirtygrandpa – it’s hilarious! Save the date for a wild (and really weird) ride on JAN 22 #dirtygrandpa”

Zac‘s Baywatch co-star Dwayne “The Rock” Johnson commented on the pic, “Nice tits brother. See you soon!” Haha!

Bigger photo below…