Most of the answers here covers Tamil, Telugu and Hindi movies acted by him, hence I felt I can write about his Kannada movies.
Kamal Hassan has acted in many Kannada movies too. Out of all his Kannada movies, Rama Shama Bhama is the one movie which I like to watch again and again.
It is a full length comedy movie. Kamal Hassan role is that of a doctor.
His character name is Shama, he is Ramesh’s friend in the movie.
He is a Dharwad man in the movie, his dialogue delivery in Dharwad Kannada is simply brilliant.
His acting as a doctor, as a friend, as a comedian is really appreciable. Especially the climax scene is real fun. One can watch this movie to see his Kannada skills :P