Bollywood director Sujoy Ghosh has signed Kangana Ranaut and Saif Ali Khan for his next project, the Hindi adaptation of the Japanese book `Devotion of Suspect X`. Kangana will play the role of a woman, who murders her abusive ex-husband and involves her neighbor in an innovative cover-up. Saif Ali Khan plays the investigator who goes all out to get to the bottom of the case once the body is discovered. Written by Keigo Higashino, it has already been made in Japanese and Korean, and is currently in the making in Hollywood. Saif and Kangana were supposed to work together in Reema Kagti`s "Mr. Chalu", but things didn`t work out. Interestingly, the two immediately received this new offer from Sujoy and both had the required dates to shoot. A romantic thriller, Sujoy`s film will pitch Saif versus Kangana. Produced by Ekta Kapoor, the film`s shooting will start in April.