Robert De Niro Stuck His Thumb Up Zac Efron's Butt Today

Zac Efron gets violated by his on-screen grandfather Robert De Niro while filming a scene for Dirty Grandpa on Tuesday (April 28) in Tybee Island, Ga.

The 71-year-old actor was seen sticking his thumb up Zac‘s butt, which caused the hot young actor to turn around in disgust.

PHOTOS: Check out the latest pics of Zac Efron

Zac has been seen on set today wearing just a pair of nude briefs while filming scenes for the film. We sure can’t wait to see what happens in the movie!

Zoey Deutch was also spotted on set that afternoon.