Being a huge fan of the singer, Ranbir, 30, said: "Whenever we talk of Kishore Kumar, all we can say is that he used to sing from his heart."
Kishore Kumar died in 1987 at the of 58. He gave the Indian film industry evergreen hits like "Chalte chalte mere ye geet yaad rakhna", "O Hansini", "Aa chal ke tujhe", "Pyar manga tumhi se", "Pal pal dil ke paas", "Hawa ke saath saath", "Chhukar mere mann ka" and "Jahaan teri ye nazar hai".
The actor also revealed that the script of the film is not ready at the moment.
"It is a great opportunity for me to act in a biopic of Kishore Kumar on screen. The script is not ready at the moment and we are waiting for Anurag Basu to complete it. It is my duty as an actor that I do full justice to it," said Ranbir who proved his versatility with films like "Rockstar" and "Barfi".
Ranbir will not be singing in the film, but "I will try my best to look and act like him".
At the moment, the actor is busy with two of his upcoming films - "Yeh Jawaani Hai Deewani" and "Besharam".