'Dilwale Dulhania Le Jayenge' - It is said that Aamir Khan was approached first for the role of Raj, but it finally landed up in the hands of Shah Rukh Khan.
'Munnabhai MBBS' - You might not believe but the role of Munna was written keeping in mind Shah Rukh Khan but due to his sudden injuries the role went to Sanjay Dutt.
'Kal Ho Na Ho' - It is said that Preity Zinta wasn’t the first choice for the role of Naina in this movie. Karan Johar wanted to cast Kareena, but due to her unreasonable charges the role went to Preity Zinta.
'Kaho Na Pyaar Hai' - Initially, Kareena Kapoor was about to make her debut in Bollywood with this movie and even shot some scenes, but she backed out from the movie and the role went to Ameesha Patel.
'Chalte Chalte' - Yes, its true Aishwarya Rai was cast before Rani Mukerji, but due to troubles caused by Salman Khan on the sets, the role went to Rani.