New Delhi, Dec 28 : Megastar Amitabh Bachchan has opened up on the challenges that he had while portraying his role in the movie 'Black', and has lauded the legendary filmmaker Sanjay Leela Bhansali for how he made it all happened with his exemplary directorial skills. The 2005 movie 'Black' is co-written and directed by Bhansali, and stars Big B and Rani Mukerji in the lead roles. The film narrates the story of Michelle (Rani), who is a deaf-and-blind woman. Amitabh plays the role of Debraj, who is the teacher of Michelle. Amitabh, who is currently the host of quiz based reality show 'Kaun Banega Crorepati 15' welcomed Lalit Kumar, from Forbesganj, Bihar to the hot seat. For Rs 10,000, the contestant was asked: 'Which of these movies does not star Kajol'? The options given were: Black, Dilwale Dulhania Le Jayenge, Baazigar, and Kuch Kuch Hota Hai. The correct answer was Black. Amitabh said: 'Rani Mukherjee starred in 'Black'', to which the contestant replied, 'You were in it too. Your role was amazing, sir.' The cine icon shared how the writer of the film is the greatest star. The 81-year-old actor said: 'People say I'm being modest but I'm telling you this. The writer of the film is the greatest star. What they write... We merely enact what is in the script. The credit goes to Sanjay Leela Bhansali. It was an incredible experience for me.' 'You see, there was a challenge in this. I'm not sure whether you noticed it or not. I had to communicate with Rani Mukherjee through my actions, by signs and gestures. But how do I tell the audience what I'm trying to gesture'? said the 'Don' actor. He said: 'So, I had to say the dialogues plus make gestures too. I had to do both. It was Sanjay Leela Bhansali who thought it all out. So, the credit goes to him.' The star then revealed that the girl who played the character of young Rani also underwent training. 'Do you know who trained her on the set? Ranbir Kapoor! He wasn't an actor back then. He was an assistant to Sanjay Leela Bhansali. He and Anil Kapoor's daughter Sonam Kapoor, who is a star now, were both Bhansali's assistants. It was his job to train the girl for the role. He trained her,' added Amitabh. /IANS