Amar Mohli is the music director. He composed the music for Varma's Sarkar.
This is Varma's second horror film after Bhooth starring Ajay Devgan and Urmila Matondkar.
Sudeep told IANS that he has been having a "gala time" working with a director like Ram Gopal Varma.
"There is absolutely no tension on the sets. And the working atmosphere is fine. There is a lot of discipline in the way things move there.
"Perhaps the environment may be different in other Hindi films, but as far as Varma's films are concerned it will be a professional set up. I accepted this film without batting an eyelid because of him. All the other things do not matter to me," said Sudeep.
One More Thought Entertainment is producing Phoonk, with ex-K Sera Sera partner Azam Khan and industrialist-turned filmmaker Parvez Damania, as partners in production.
The film will also be made in Telugu under the technical supervision of Ram Gopal Varma.
However, Sudeep is not acting in the Telugu version. "I accepted the Hindi film only because of Varma. My heart is in the Kannada film industry. I am loved by the people here, my family is here. Why should I migrate to a new place where I am not sure of anything. I would certainly concentrate on Kannada films," said Sudeep.