Actor Rajpal Yadav revealed that he was supposed to play the titular role in the film 'Billu', adding, "However, I was later given a different role, and Irrfan Khan bhai played that character." Rajpal praised Irrfan’s performance, calling him “amazing as Billu”. Notably, the 'Malamaal Weekly' actor portrayed the character of 'Jhallan Kumar' in the movie.