Zac Efron and Robert De Niro have a flex-off on the set of Dirty Grandpa

MORE photos have emerged of a shirtless Zac Efron on set, only this time he’s joined by Robert De Niro and the pair are performing some pretty bizarre stunts.

Zac Efron and Robert De Niro strip for a flex off on the set of 'Dirty Grandpa'

THINGS got a little weird on the set of Zac Efron and Robert De Niro’s latest movie Dirty Grandpa.

But still sexy of course, because Efron.

The pair, who star together in the upcoming comedy, whipped off their shirts for a flex-off and a couple of handstands and push-ups while shooting scenes on Tybee Island, Georgia.

The bizarre shots might even top the 27-year-old hunk’s amazing fringed crop top moments and beige underwear strutts we were treated to earlier this week.

But let’s not overlook De Niro, who looks to be in incredible shape at 71.

51726279 Actors Zac Efron and Robert De Niro take off their shirts for a Flex Off contest for a scene in their new movie Dirty Grandpa on April 30 2015 in Tybee Island Georgia The new comedy tells the story of an uptight guy who is tricked into driving his grandfather a perverted former Army general to Florida for spring break Actors Zac Efron and Robert De Niro take off their shirts for a Flex Off contest for a scene in their new movie Dirty Grandpa on April 30 2015 in Tybee Island Georgia Robert showed his strength as he hoisted Zac onto his shoulders FameFlynet Inc Beverly Hills CA USA 1 818 307 4813

Dirty Grandpa tells the story of an uptight guy (Efron) who is tricked into driving his grandfather (De Niro), a perverted former military general, to Miami for spring break just before he is due to be wed.

UK CLIENTS MUST CREDIT: AKM-GSI ONLY Zac Efron and Robert De Niro strip for a flex off on the set of 'Dirty Grandpa' in Tybee, Georgia. Pictured: Zac Efron and Robert De Niro Ref: SPL1013185 300415 Picture by: AKM-GSI / Splash News

UK CLIENTS MUST CREDIT: AKM-GSI ONLY Shirtless co-stars Zac Efron and Robert De Niro performed their own stunts for 'Dirty Grandpa' on Thursday for a huge crowd of extras in Tybee Island, GA. The pair first had a "flex off" before Robert De Niro proceeded to throw Zac over his shoulder, eventually "balancing" Zac on one forearm while Zac did a handstand. Pictured: Zac Efron and Robert De Niro Ref: SPL1013411 300415 Picture by: AKM-GSI / Splash News