Mumbai, Feb 5 (IANS): Actor Randeep Hooda has lost 18 kg in just 28 days for his upcoming film "Sarbjit", the film's director Omung Kumar has revealed.

"Sarbjit" is a biopic on Sarabjit Singh, an Indian farmer who was convicted for terrorism and spying in Pakistan and was sentenced to death. He was attacked by inmates at a prison in Lahore in April 2013 and died a few days later.

"When I had approached Randeep for this role, I was very clear in my mind that I need someone who is open about going through a rigorous weight loss, as the role demanded lot of different looks," Kumar said in a statement.

"Randeep took that as a challenge and agreed upon giving 100 percent dedication not to prove that he can do it as an actor but to do justice to the character and the film.

"The role needed Randeep to look very fragile with his bones being visible. He shed around 18 kgs of weight in 28 days, went through a strict diet and in fact in the last few days he was living completely on water," added Kumar, who is mighty impressed with Randeep.

Kumar also shared a photograph of the transformed "Kick" star on Twitter.

"@RandeepHooda salute to your dedication, lost 18 kg in 28 days, making a statement #Sarbjit," Kumar captioned the image.

"Sarbjit" is slated to hit the screens on May 19, a day before it was scheduled to hit the screens.