Mumbai, Aug 19 (IANS): Rahul Thackeray, who will direct the biopic on his grandfather and Shiv Sena founder-leader Balasaheb Thackeray, says he owes his entire filmmaking knowledge to director Rajkumar Hirani.

Rahul's mother Smita Thackeray is the producer of the biopic.

Asked what he had learned from Hirani while assisting him on "PK", Rahul said: "It's not just tips, but my entire learning is from him.

"I've learned a lot of minute details in the time I spent with him. So hopefully in the future, when I'll make a film, I would like to apply the aspects that I've learned."

Smita Thackeray said the biopic was "a big challenge for him (Rahul) and he's taken up the challenge".

"We all are very happy that we're together and we'll definitely like to bring something great for you. The script is currently being written and once the script is done, we'll make the film," she said.

Rahul is currently involved in the story, screenplay and research for the film.

He underwent a course in filmmaking in Canada, and after coming back to India worked as an assistant director in the blockbuster film "PK".