The actor has been asked to shed his muscles for his next film

Actors are pushing the envelope today when it comes to portraying various on-screen personas. Robert De Niro gained 60 pounds for Raging Bull, while Aamir Khan beefed up for Ghajini and lost it again for 3 Idiots.

Now Vivek Oberoi has gone on a muscle-losing spree for his next, Gyaarah Chaalis Ki Last Metro, after building his physique for Zilla Ghaziabad.

The actor, is believed to have taken time off to reduce his muscle built. According to a source close to the actor, "When director Sanjay Khanduri told Vivek that he couldn't look bulky for Gyaarah Chaalis ¦, he agreed. After wrapping up Zilla Ghaziabad, Vivek started a different exercise regime."

For the sequel to Ek Chaalis Ki Last Local, the actor is also required to lose weight. "He has to look lean. He's lost about four kilos in the last couple of weeks. By the end of this month, he'll have shed 10 kilos, " said our source.

Besides a different workout regime, comprising cardio and free-hand exercises, the actor also has to follow a strict diet plan. "Vivek's cut down his protein intake.

He eats small meals every two hours comprising brown bread sandwiches, salads and sprouts. Lunch and dinner include a couple of chapattis with a bowl each of vegetable and dal, " explains our source, adding that he's banished sweets for a while now.

When contacted, Vivek said, "Yes, I've already lost four kilos and have to shed a few more. And I'm watching my diet for that." Interestingly, his physical transformation does not end here. He is supposed to get into shape again for the Krrish sequel.