John on Wednesday took to Twitter, where he shared a photograph of the film's clap-board and captioned: "Day 1.. 'Parmanu. The Story of Pokhran'. Our biggest test ever!" "Parmanu - The Story of Pokhran" also stars Diana Penty and Boman Irani. John has also written the film along with Saiwyn Quadros and Sanyuktha Chawla Shaikh (writers of "Neerja"). The music of the film is helmed by Sachin-Jigar. "The road to Pokhran has been paved. It's time to embark on a journey to revisit the mission that changed the place of India on the world map and turning the course of modern India's position in the world as a strong nuclear state," John said in a statement. The film is slated to release on December 8.