The only reason Ajay Devgan agreed to do the film was because his home production Shivaay got delayed. This gave him 3 free months.Seeing that he was not busy, the producers approached Ajay and promised him the film would be completed in 12 weeks.
The movie is inspired by the Malayalam story written and directed by Jeethu Joseph. As a possible tribute to him, when Ajay Devgan's character makes an entry in a hotel register, he signs his name as Jitu Joseph.
Some of Drishyam's plot is similar to the Japanese novel 'The Devotion of Suspect X' by Keigo Higashino. Ekta Kapoor, who acquired the rights of this novel in India, sent a legal notice to the makers of the Malayalam movie.
Commentator Nandini Ramnath noted how the denial of even slight inspiration by the Japanese novel is parallel to the inside movie storyline as "Jeethu Joseph's achievement lies in lifting an intelligent concept and localising it so effectively that the links (to the Japanese novel) appear tenuous unless closely investigated. "Drishyam' is the perfect crime about a perfect crime, and its director's alibi is almost as airtight as the one Ishigami creates for Yasuko and Misato."
In November 2014, it was announced that Ajay Devgn would star in the Hindi remake of the 2013 film 'Drishyam", which will be produced by Viacom 18 Motion Pictures in association with Panorama Studios and directed by Nishikant Kamat.
The trivia items below may give away important plot points.
Despite Head of Police Meera Deshmukh (Tabu) going to great lengths for her son Sameer Deshmukh (Rishabh Chadha), they do not have any scenes together during the entire movie. Neither does Sameer Deshmukh have any scenes with his father.