JP Dutta's Paltan was supposed to be a comeback for Abhishek Bachchan but the actor pulled out of the film at the last minute and the director said that he is clueless about the reason behind the actor's departure from the project.
It was with Dutta that Abhishek made his debut opposite Kareena Kapoor in the veteran director's Refugee in 2000.
He later collaborated with the director again on the films LOC Kargil and Umroa Jaan.
Abhishek was initially attached with the war-drama but he reportedly backed out of the film two days before the shooting commenced.
When asked why Abhishek backed out of the project, Dutta told reporters, "Please go and speak to the Bachchans and let me know, because even I don't know."
Abhishek was replaced by actor Harshvardhan Rane, who has now bagged a three film deal with Dutta.
Paltan is based on the 1967 Nathu La and Cho La clashes between the Indian and Chinese armies. It stars Jackie Shroff, Arjun Rampal, Sonu Sood, Gurmeet Choudhary, Siddhanth Kapoor, Rane and Luv Sinha.
The 68-year-old returns to direction after Umrao Jaan, which released in 2006.
Dutta said he was born to make films and he finds happiness when he is directing.
"I was born to do this job. For me, happiness lies in making films. When director I'm not making one I'm sad... When you are young you realise what your calling is. I think I've been sent to do this. To make our soldiers immortal," the director said.
Paltan is produced by JP Films and presented by Zee Studios and is scheduled to release on September 7.
(With PTI Inputs)