Ranbir Kapoor will soon begin shooting for Sanjay Dutt’s biopic with Rajkumar Hirani. Ranbir has been working out in the gym to have the body type of Dutt and will shoot for the latter’s life having four different looks. Buzz is that the Kapoor lad will have no prosthetics or makeup to change his look to match that of Sanjay Dutt’s. Ranbir will have to grow his hair, beard and change his body in accordance to the need of the character. What’s more? The actor will take help of specialized diet and gym workouts to build his body.