"Haji Mastan is just a reference. Whatever film we do, it's a reflection of society. I am not doing his life story. It's just a reference point. The film is absolutely fiction and every character has its own energy and attitude, " Ajay, 41, told in an interview about the film that has been dragged to court.
"Some similarities might emerge. Someone asked me that in the film the character is in love with a heroine, which apparently happened in real life too, and he works in the dock, but Amitabh Bachchan did that too in 'Deewar'".
Haji Mastan's daughter Shamshad Supariwala has filed an additional affidavit in a Mumbai court against Balaji Telefilms, the producers of "Once Upon A Time In Mumbaai", demanding that the family be shown the film before its release.
This is not the first time the movie directed by Milan Luthria has faced trouble. Earlier, Haji Mastan's adopted son Sundar Shekhar alias Suleiman Mirzha filed a suit for an injunction order against its release, but a city civil court refused.
The court, however, directed the makers of the film to carry a disclaimer that it has no resemblance to the life of Haji Mastan, who died in 1994.
Ajay says it was a report that came out a long time back that landed the film in legal trouble.
"One story came out long back and that became a perception. I don't think anyone of us further has mentioned anywhere that I am playing Haji Mastan, " said Ajay.
"When the case is in court I can't comment but am sure they will understand once they see the film, " he added.
Ajay can't recollect too many stories of Haji Mastan.
"I must have heard of Haji Mastan in my childhood but can't recollect what exactly. But there was something about Haji Mastan which made people say good things about him too, " said Ajay.
The National Award-winning actor insists that his character in "Once Upon A Time In Mumbaai" is more similar to Robin Hood, unlike his role in "Company" (2002) where again he had played a don.
"He is like Robin Hood. He is romantic; he has a sense of humour, which was not there in 'Company'. When so many shades come to a character and when it shows that the person at heart is good, the perception of performance changes, " said Ajay.
Sheduled to release Friday, the underworld saga also stars Kangana Ranaut, Emraan Hashmi and Prachi Desai.
The actor prefers not to connect with his characters too deeply. "When you are playing a character you have to like that character and think from its point of view, otherwise you can't play that character. But I don't connect much with the character.
"If you think a lot about the character, you will go mad and forget which is you in real life. Most people become mad if they keep living the character even after going home. The first thing you should learn is to switch off, " he said.
But Ajay did take a long time to come out of the character of Bhagat Singh which he played in "The Legend of Bhagat Singh" (2002).
"It was not a hangover but there was an admiration for the character of Bhagat Singh. When you are playing a real life character, you have to justify it fully because he is a real life hero. You can't afford to make minor mistakes while doing such characters. So, you have to study a lot.
"When you see that a person can be so selfless, you start feeling. That was the only character that stayed with me for a while, " said Ajay.