Mammootty spent 'two full days' obsessing over his script—and he arrived on set ready to deliver.

Rajkumar Periasamy's OM - Chapter 1: Udhiram - The Blood Wood is one of the most anticipated films of the year. The Tamil film will see Mammootty, Dhanush and Sai Pallavi in lead roles. Ahead of the release, Rajkumar spoke in detail about the casting of OM in an interaction with Galatta Plus, and shared how Mammootty joined the cast of the film and made sure he knew the script by heart even before the shoot began.

Mammootty is often considered one of the best and most prolific actors working in the Malayalam film industry. He recently won his fourth National Award for Best Actor for the horror film Bramayugam.

During the interaction, Rajkumar shared how 10 days before shoot, Mammootty called him to Kochi at his residence to have a script reading. The director said, "He called me to Kochi and spent two and a half days, except for the night hours, where he wanted me to read the script and he would just listen to it. The full first half and then the second half, and the half day for his scenes, so that was his process."

He added that it was not a normal script reading but one where he went through all the plot points and the arc of all characters and how the story evolved. The actor went through the dialogues of each and every character, from the first line itself. The director shared that the veteran actor would also clear his doubts during this time and ask about the smallest of details. "He would want to know more about these... so when he came [to set] he was fully prepared," said the director.

OM marks Mammootty's return to Tamil cinema after a gap of seven years. Sai Abhyankkar composes the music, Ezhil Arasu K. handles the cinematography, and R Kalaivanan is the editor. The film also features A. Pannerselvam as Art Director, with Yannick Ben and Kecha Khamphakdee handling action choreography.

The film is produced by Shraddha Agrawal, Dhanush and Azmat Jagmag.