Iconic Hollywood actor Robert De Niro had a bit of fun with his co-star Zac Efron while out on a press stint for their upcoming comedy flick, Dirty Grandpa. 

The pair appear to get on famously and even made this hilarious video for Funny or Die. 

Zac, clearly enamoured by his very esteemed co-star, is looking for some acting tips and while he believes he is getting a metaphorical lesson in acting from a screen legend, Robert actually just wants a sandwich. 

Dirty Grandpa is out later this month and features Zac as an uptight guy who is tricked by his dirty-minded grandpa into driving him to Florida for Spring Break. 

Yeah, we can't wait to see this one if only for the reams of topless photos of Zac that have surfaced from the set of the movie. 

Yep, well worth a watch. 

Watch the hilarious Funny or Die video below: