This film's title was kept as Raja Kaka to pay respect to Rajesh Khanna. Rajesh Khanna was called fondly as Kaka by his friends and as King of Romance by media. So the tile became Raja Kaka. Rajesh Khanna was signed for the film but later opted out.
It was during the making of the film that Imtiaz Khan had made some nasty comments about Rekha. Kiran Kumar found out about this and beat him up very bad.