When asked whether he expected the award, he said: "I don't think about awards and such diversions. I think only about music."
Starring Mammootty, the film revolves around King Kerala Varma Pazhassi Raja who revolted against the erstwhile British East India Company when they imposed high revenue policies upon the people of Kottayam kingdom.
Ilayaraja also thanked director Hariharan and production team executive Pravin for their support during the making of the film.
"I composed the score in 15 days and sent it to Budapest... We recorded it with a symphony orchestra, " he told reporters Wednesday after the 57th National Film Awards were announced.
Speaking about the art of composing music, he said: "Mere keyboard playing is not composing music. When I did this background score ('Kerala Varma Pazhassi Raja'), I envisioned each shot, the story and how it was going to be executed on screen and felt the music and situation.
That is composing... when you create something, the feelings of the director should get translated into the music. This has happened in this ('Kerala Varma Pazhassi Raja')."