Blockbuster director Rajkumar Hirani, who delivered the successful 'pk' last year, says he will begin the biopic on actor Sanjay Dutt next year.

Clarifying news related to the project, Hirani told media persons here: "I'm working on the script of Sanju's biopic. And we'll be starting the film next year."

About the casting, Hirani said: "I haven't even thought about casting till now. We are writing the script and only once it finishes, we'll be able to see how the characters come across and who would be apt to play the characters."

There were reports that Ranbir Kapoor has been finalised to play Sanjay, but Hirani cleared: "Ranbir is the only one I've spoken to about the film."