Development Reports for Mammootty's upcoming film came on 25 May 2024 soon after the release of his film
Turbo. It will be directed by Jithin K. Jose in his directorial debut, who previously worked as a writer in the film
Kurup. Other details on crew that included were cinematographer
Jomon T. John and music director
Sushin Shyam. In September 2024,
Vinayakan was reported to play a prominent role in the film that brings together Mammootty and the former after a while, and was last acted together in
Daivathinte Swantham Cleetus (2013). Their past works were in
Big B (2007) and
Best Actor (2010). As per reports, Vinayakan's role was originally meant for
Prithviraj Sukumaran.
Roby Varghese Raj's inclusion was also reported in 2024. Filming commenced on 25 September 2025, under the working title
Production No. VII that marks the seventh production venture of Mammootty Kampany. The screenplay is co-written by Jishnu Sreekumar and Jithin K. Jose himself. The yet to be titled film's technical team after changes included cinematographer Faisal Ali and editor Praveen Prabhakar.
Wayfarer Films will distribute the film in
Kerala. The official title
Kalamkaval was announced by makers on 15 February 2025, that has a tagline "the venom beneath." The film would also have music composer
Mujeeb Majeed while the action sequences are choreographed by stunt director Action Santhosh. Last year in an interview with
John Brittas, Mammootty said that the film would be another attempt at experimenting with roles he had not done before.
Filming and casting Filming started with a muhurth puja ceremony on 25 September 2024 in
Nagercoil. Mammoooty joined the set on 2 October 2024. The film completed its shoot in 9 November 2024. It was extensively across locations in Tamil Nadu.
Rajisha Vijayan, who did her last role in
Madhura Manohara Moham is one of the leading lady in her first association with
Mammootty, making her comeback after 2 years.
Gayatri Arun is another female lead in her second collaboration with Mammootty after
One, where he played the role of the
Chief Minister of Kerala. Gibin Gopinath,
Shruti Ramachandran,
Azees Nedumangad,
Kunchan,
Biju Pappan,
Malavika Menon formed rest of the cast. Director Jithin K Jose revealed that actor Prithviraj Sukumaran was initially considered for the role that Vinayakan has played. When Jithin narrated the script to Prithviraj, he suggested that in either of the roles, Mammootty could fit in. However, due to Prithviraj's busy schedule with
L2 : Empuraan and other films during that time, Jithin looked for other options. It was then later Mammootty who recommended to give the role to Vinayakan. ==Music==