"We have begun working on it. It has taken time because the film should be better than the first two instalments, so we didn't want to hurry. We've finally cracked a great concept," Hirani said here on the side lines of the 17th Jio MAMI Mumbai Film Festival.
He assured that the third part will definitely feature the popular duo Sanjay and Arshad as Munna and Circuit, respectively.
"We usually don't think of casting until the script is finished. But Sanjay and Arshad will definitely be part of the project," he added.
"Munnabhai M.B.B.S" and "Lage Raho Munna Bhai" were so successful that they were even remade in southern languages such as Tamil and Telugu.