Veteran actor Thilakan, 74, is in a critical condition after suffering two heart attacks, doctors treating him in Thiruvananthapuram said on Saturday.
The actor from Kerala has been part of nearly 300 films, most of them in Malayalam.
Thilakan has been put on the ventilator.
Beginning his career in the fifties, he became famous with his 1979 film Ulkadal. His latest film, Ustad Hotel, is currently running in theatres.
The actor was in news for taking on the Association of Malayalam Movie Artistes, leading to his ouster in 2010.