Directed by Rakeysh Omprakash Mehra, "Mirzya" pairs Harshvardhan opposite newcomer Saiyami Kher, niece of Tanvi Azmi.
The film, penned by Gulzar, is a take on the tragic love story of Mirza-Sahiban.
"To go from being a non-rider to a very accomplished rider and archer, it took 18 months to emotionally get to that point...To physically transform for the character was the most difficult thing," Harshvardhan told PTI, when asked what was the most challenging part of doing the film.
While shooting in Jaisalmer, Harshvardhan fell off the horse. He got up and continued to shoot, but soon collapsed on the set due to dizziness. Later, at the hospital, it was found that he had suffered head concussion.
"I had a concussion to the head because I accidentally landed on the back of my head during a scuffle sequence," Harshvardhan said.
The film is scheduled to release on October 7.