"Gunday", also featuring Ranveer Singh, is based in the 1970s Calcutta (now Kolkata) and both the actors had to get their body tanned to match the skin tone of people there and make it look more realistic.
"I had it more difficult than Ranveer Singh as he had to go only two shades darker. For me, it was almost four shades," Arjun said in a statement.
It took approximately three hours for both the male lead actors to put on the tan make-up and two hours to get it off each time.
"Gunday", which also stars Priyanka Chopra, releases Feb 14.