51726756 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. FameFlynet, Inc – Beverly Hills, CA, USA – +1 (818) 307-4813