It appears that when Rajkumar Hirani took the decision of making a biopic on Sanjay Dutt’s life, not just the audience even his producer was surprised. While conversing with Telegraph, Vidhu Vinod Chopra accepted that he was not aware when Hirani brought him the idea of Sanju. He said that when Hirani told him regarding the film he responded by asking that what is there in Sanjay Dutt’s life that could be made into a film. He said that he told Hirani to make a movie on his life instead, that how he left Kashmir as a young boy and struggled after reaching Bombay.
Chopra said that he thought that Raju and Abhijat—the co-writer of Sanju had actually lost their minds.
But, the bond that Sanjay Dutt and his father Sunil Dutt shares made Chopra give up on Munna Bhai Chale Jail for Sanju. He said that when Hirani narrated him the entire occurrences of Sanju’s life, he was dumbfounded! Initially, according to Vinod Chopra he thought it was all gibberish and that Sanju was not somehow telling Raju Hirani entire truth, however, when they both started researching all the provided details—from the three hundred and eight girlfriends Sanjay Dutt had to how he had to beg on the streets of United States for money so that he could purchase a bus ticket—they realized that everything told by Sanjay Dutt is nothing but true.
Chopra was surprised to realize that the tears that Sanjay Dutt had in his eyes in Munna Bhai MBBS in the scene where he had to ask his father for forgiveness were real. He informed to the newspaper that standing on the set of that scene he had no idea that they were actually living that scene.
Another decision of Raju Hirani that Chopra consented to was the decision of casting Ranbir Kapoor in the movie. Chopra said that he was informed that Ranbir Kapoor has been considered for the role, he was unhappy to hear this as he thought someone like Ranveer Singh could have done much justice to the role. Vinod Chopra said that he thought that Ranveer had the splendour, the emotional depth and the ability to completely transform himself as per the role requirements. However, Hirani was obstinate about his decision and was sure that Ranbir would be the best choice for the role. He added that when the shooting began Ranbir became Sanjay Dutt and he, without doubt, has to take back his words.