His story was used when researching the film.[15] He was also trained by Harpreet Singh, who was a coach of the Indian boxing team.[16] Singh did not disclose to his coaches that he was preparing for a film role.[9] His trainers said that Singh was learning boxing at the age when boxers usually retire.[16] Singh's training began at the Netaji Subhas National Institute of Sports, Patiala, a year before filming.[8][10] During training, he could not see punches coming and took a real beating every day, at one point breaking some ribs.