India, Nov. 13 -- 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 residen...