Apart from learning how to use a machine gun for Paltan, Luv Sinha also met his muse, Attar Singh, 2/Lt during the Sino-Indian clashes of 1967. Sinha, who plays the character of Singh in the film, tells mid-day, "Meeting him in Leh during the initial days of our shoot was an honour. His contribution towards the country during the clashes cannot be forgotten. His bravery was acknowledged by his superiors too. It is a privilege to portray him; a responsibility that I took seriously."

Even though Sinha learnt from Singh about the battle, including his "experience and about the injuries he sustained," he kept from aping the man for reel. "I didn't discuss the deeper details with Attar Singh Ji because I wanted to follow JP [Dutta, director] sir's lead, and develop the character based on what he had in mind."