New Delhi, September 5 (ANI): Zac Efron and Robert De Niro are in talks to star together in road trip comedy ' Dirty Grandpa ' that will be directed by Dan Mazer. According to the Hollywood Reporter, Efron will play a young man who is tricked into driving his grandfather portrayed by De Niro to Florida for spring break. De Niro will be play a perverted former Army general who thinks his grandson is about to marry the wrong woman. The movie will be produced by Barry Josephson.