For a song scene, Ranbir Kapoor had his co-stars Kalki Koechlin and Aditya Roy Kapoor drink real vodka out of shot glasses!

While Ranbir Kapoor is known to be an intense actor, his friends recently got to experience his fun side too.

The actor played a prank on the sets of his upcoming film on his co-stars Kalki Koechlin and Aditya Roy Kapoor. While shooting for one of the scenes in Yeh Jaawani Hai Deewani, RK replaced the water in a couple of shot glasses with real vodka.

A source from the sets says, `A song sequence required Kalki and Aditya to drink from shot glasses. As is the usual norm, water was poured into the glasses. But Ranbir decided to replace the water with actual vodka. Both his co-stars were left quite shocked.`

But once they realised Ranbir's prank, Kalki and Aditya apparently doubled up in laughter. The source adds, `The expression on their faces was priceless!`