"In my 20 years of association with Rahman, I still haven't figured out how he works because he is full of surprises. For Kadal, he composed a song a called Moongil thottam when I was out of town. He made me listen to the song after I returned and I was stunned," Ratnam said.
"Sometimes he has played few compositions to me which he claims to have composed on flight. I wonder how did even manage to compose a tune on flight with no instruments," added the filmmaker. Kadal features debutants Gautham Karthik and Thulasi Nair. It tells the story about the lives of Christian fishermen. The cast also includes Arvind Swamy, Arjun, Lakshmi Manchu and Thambi Ramaiah in important roles.