Acclaimed filmmaker Srijit Mukherji revealed on Tuesday how Vidya Balan, who has been known for her jovial and down-to-earth personality, completely transformed herself to no-nonsense brothel madam 'Begum Jaan'.

"Before we started shooting 'Begum Jaan' we organised two workshops simultaneously. One with Vidya, another with girls... because Vidya is a jovial down-to-earth person and she easily mingles with everybody on set and I didn't want that. I wanted certain kind of distance with the girls from Vidya," he said at the trailer launch of the film.

"Vidya used to ask many questions during the workshop like what the memories of 'Begum Jaan' were when she was three, when she was first exploited or what happened when she got married. So at the end of the workshop, I had already completed writing four scripts... one 'Begum Jaan' and others are the prequels and sequels. I had to keep ready all the backstories of 'Begum Jaan' and the girls," added the 'Zulfiqar' helmer.

"After the workshop when Vidya entered the set, I saw 'Begum Jaan' who is a fierce, manipulative no-nonsense kind of woman, walking in. There was no trace of Vidya Balan," he told the media.

The National award-winning filmmaker said the 'Kahani' actress has an immense commitment towards her craft.

Srijit Mukherjee's directorial is a Hindi adaptation of Bengali film "Rajkahini", which saw Rituparna Sengupta in the lead, and also marks his debut in Bollywood.

Vidya is portraying the character of a brothel madam, while Ila Arun, Gauahar Khan, Pallavi Sharda, Ridheema Tiwary, Ashish Vidyarthi, Chunky Pandey and Rajit Kapoor are portraying the pivotal roles in the film.

The hard-hitting plot deals with the trauma of displaced women in a brothel during India's partition. While 'Rajkahini' was based in Bengal, 'Begum Jaan' is based out of Punjab.

Produced by Mukesh Bhatt, the film is scheduled for release on April 14.