Actress-producer Dia Mirza has joined the cast of actor Sanjay Dutt`s biopic, being helmed by Rajkumar Hirani. Dia shared the news on Twitter, saying she is happy to be on board for the project. She posted: "The happiest place in the world is a Rajkumar Hirani film set. Sanjay Dutt biopic, Ranbir Kapoor, Vicky Kaushal." Ranbir, who was last seen on the big screen in filmmaker Karan Johar`s multi-starrer "Ae Dil Hai Mushkil", will essay the role of Sanjay in the upcoming biopic. Dia also shared an image of the cast cutting a cake together on the set. Earlier, Hirani had shared that the first shot for the biopic has been taken and there is excitement among the film`s team. He had tweeted on Saturday: "First shot taken now for Sanjay Dutt`s biopic. Canning a very funny scene. The excitement in cast and crew."Source: The Statesman