Deepak Ramsay's was to cast Celina Jaitley in KOI MERE DIL MEIN HAI but could not because of her commitment for Feroz Khan's JANASHEEN. This paved way for Diya Mirza to replace Celina. But Deepak was not too sure if Diya would be as bold as Celina, but surprisingly she gave her green signal justifying that if the character and situation demanded then what's the harm. And so here is Diya in KOI MERE DIL MEIN HAI, playing a modern girl who wears bold outfits. She makes heads turn wherever she goes. She is not a brat but she nurses this belief that she can get any man she wants. One man refuses to be bowled over and she starts chasing him. Slowly she realizes what is true love and turns over a new leaf.

KOI MERE DIL MEIN HAI is a story revolving around four young people - Raj, Simran, Sameer and Asha.

Raj (Priyanshu) is the spoilt son of Mumbai based Millionaire, Vikarm Malhotra (Kadar Khan). Raj is a young guy who likes to live life to the fullest; afraid that her son may be falling into bad company Raj's mother (Reema lagoo) gets him engaged to Simran (Diya Mirza).

Simran is the daughter of a rich NRI (Sadashiv Amrapurkar) and she studies in Dubai. Simran too is naughty by nature and believes in enjoying life and having fun. Simran meets Sameer (Rakesh Bapat) who is a young singer and musician from Mumbai and has come to Dubai with the troupe to perform at various clubs of Dubai.

Simran is totally taken by Sameer's charming character and innocence and falls in love with him.

Raj on the other hand meets Asha (Neha) who gives tuitions to Raj's kid sister Sonie. Raj is totally mesmerized by the simplicity and innocence of Asha and feels that she is the only right girl for him.

A Quadrangle Love Story evolves among the four main characters of the film and a very interesting climax develops when the parents get involved.

KOI MERE DIL MEIN HAI, slated to release on the 13th of May, is a light fun - musical entertainer with loads of inherent comedy situations and no violence of any kind.