Filmmaker Rakesh Roshan revealed Shah Rukh Khan initially backed out of 'Karan Arjun' and they replaced him with Aamir Khan. Roshan added Shah Rukh later came back because he was the first person to sign him as an actor in 'King Uncle'. "He said, 'I couldn't sleep...I don't believe in the story [but] I'll still work with you'," said Roshan.