This film originally had Dev Anand in the leading role, but following a spat between him and producer Nasir Hussain, he walked out of the film. When Shammi Kapoor was approached for the role, he told Nasir Hussain he would work in the film only if Dev Anand tells him personally he is not working in the film out of his own will, and that he is fine with him doing the film. That is what happened.
The drummer in black, when Shammi sings "O haseena" and other hit numbers, is none other than Saleem Khan, Salman's father!
At first 'Shammi Kapoor' was not happy with producer Nasir Hussain's choice of music director, Rahul Dev Burman. He wanted Shankarsingh Raghuwanshi, claiming that his music perfectly captured the rhythm of his body/dance. However, when Kapoor heard Burman's first song "Aaja Aaja Main hoon Pyar Tera", he changed his mind, impressed.
Premnath wanted to be a hero like his BIL Raj Kapoor. But couldn't really make it. This movie marks the second phase of his career. - as a character actor and villain. The really shone this time.
Shammi Kapoor's wife Geeta Bali died during the shoot of the movie and the love-drunk Kapoor went haywire and canceled the shoot. The movie was in-hold for 3 months by directer Nasir Hussain waited for Kapoor.