Anurag Basu, whose "Barfi!" did exceedingly well at the box office, says he was initially confused about his lead actress for the film.
While Ranbir Kapoor played the title role, Priyanka Chopra was seen as autistic Jhilmil Chatterjee and her performance won her many awards. Illeana D'Cruz also featured in the romantic-comedy.
"When I went to cast Priyanka Chopra, I realised that I could not see her as my character. I told her that I was not sure and that we should have a three-day workshop," said Basu.
The director was speaking at an acting workshop - 100 years of Indian Cinema: An actor Prepares" - held on the second day of the ongoing 14th International Indian Film Academy (IIFA) awards and weekend here. It started Thursday.
He further said: "The first day of the workshop was tough as Priyanka was very formal. I asked her to hold my collar and shout abuses at me, this loosened her up a lot."
"I told her to see the world from my character's eyes and everything will fall into place. She just had to be there in the moment," he added.
How do you usually cast for your films?
"I need to have clarity in my mind. As long as there is clarity, I can choose my cast in one go," he said.
The director, who has directed films like "Barfi!", "Life in a ...Metro" and "Gangster - A Love Story", describes the current lot of actors as easy-going.
"All the actors of our generation are easy-going. But all of them are different. Hrithik Roshan is more reserved, while Ranbir and I became great friends as we have the same likes and dislikes. You have to balance everything as a director," he said.