The 'Aashayein' actress believes that Manto has his set of huge fan following owing to his literary works, which will bring the target audience to the theatres.
"Manto is our Shah Rukh Khan. He is our biggest USP. Manto was a huge star in himself. He has a rich legacy, his set of fan following and people who have closely followed and admired his work.
There are so many who are eager to watch the film simply because it is based on his work," Sonal told PTI.
The film brings to celluloid Manto's some of the most controversial stories - 'Khol Do', 'Thanda Gosht', 'Aakhri Salute' and 'Assignment'.
Sonal, who features in "Thanda Ghost", plays the role of a mistress to a man who goes missing during India-Pakistan partition. The woman is then concerned about her uncertain future.
For the 'Damadamm' actress, who is "big fan of Manto", the fact that she had to keep the character free from any judgement, from herself and the audience, was a challenge.
"She is a feisty sardarni. You don't know whether to feel bad for her or hate her. One minute she will come across as selfish and the other minute you would understand her concern.
"I didn't want to judge the character at all. And to play it in a certain way where even the audience doesn't judge her was challenging. She is just a practical woman who behaves that way because of certain reasons," she said.
Directed by Rahat Kazmi, "Mantostaan" deals with the issue of India-Pakistan partition. The film will mark the return of Sonal in realistic cinema after her debut in the national award winning director Nagesh Kukunoor's "Aashayein" opposite John Abraham.
The actress, who then went on to work in films like "Radio", "Damadamm", both co-starring Himesh Reshammiya, and "Future to bright hai ji", says she never enjoyed commercial cinema that much.
"It is definitely great to be back in the zone of 'Aashayein'. I started out with that film and then did a few commercial movies. But honestly, I never enjoyed them as much.
"Masala films are good with song and dance, but the joy of working in a brilliant film with a great director is something else. I am glad to be in this space of movies," she added.