Actor Emraan Hashmi's character in 'Once Upon A Time in Mumbaai' required him to shed a lot of body fat and weight in an unreasonable time frame.

Once the script was narrated and Emraan was on for the film, Milan wanted Emraan to lose a considerable amount of body fat and put on lean muscle mass in just four months.

"Anyone who is into fitness, knows that it is an unreasonable time frame...Emraan started something called angular training... and once he started he wanted to see results faster and Emraan went ahead and took fat burners for a month without consulting his trainer.. He was already training twice a day, which put him into the over-training zone...

"Fat burners put an even more unwanted stress on his body, his cortisol levels shot up and he fell seriously ill, with chronic fatigue. Because of which Milan had to postpone some key shooting sequences and portions of the pee loon song for a later date, " revealed a source very close to Emraan.

Emraan is playing the role of Shoaib, an evil underworld prince who is Sultan's (Ajay Devgan) protégé. Shoaib becomes the reason for the downfall of Sultan.

It is said that the movie is loosely based on the life of Haji Mastan and Dawood. However, like Emraan, even the makers of the movie have denied any such news.