Akshay Kumar...... Agastya Rao
Salman Khan...... Suhaan Kapoor
Preity Zinta...... Piya Goyal
Anupam Kher...... Vakil Chachu
Aman Verma...... Zubin
Javed Sheikh (Pakistan)...... Samrat Goyal
JAAN-E-MANN begins with Suhan [Salman Khan] receiving a notice to pay the alimony. He has to shell out Rs. 50 lacs to his estranged wife Piya [Preity Zinta], now settled in the U.S. Suhan's 'Chachu' Boney [Anupam Kher], a lawyer, thinks of ways to wriggle out of the situation.
It's at this juncture that Champu aka Agastya [Akshay Kumar] walks in, looking for Piya. He was in love with her during the college days, he tells Suhan and Chachu, but she was in love with someone else [Agastya is unaware that Suhan is the guy]. Piya had ignored Agastya then, a nerd, and even broke his heart by courting another guy. A heartbroken Agastya had left the college for this reason.
Back to the present: Agastya is now at NASA. His outwardly appearance may've undergone a change, but he still doesn't know how to communicate with a girl, forget dating her. Suhan and Chachu hatch the plan to get Agastya and Piya together, so that Suhan is out of the mess.
Agastya flies to New York, so does Suhan. They hire an apartment right opposite Piya's residence and monitor each and every move of her through binoculars and telescope. Suhan helps Agastya to woo Piya. A reluctant Piya eventually gives in. But the story changes when Suhan gets to know of a certain reality and that changes his life completely. He feels responsible towards Piya.
Suhan realizes his folly and wants to make amends. But oblivious to Suhan's presence, Piya is now preparing for a life with Agastya. One wouldn't like to reveal the climax, since that would take the sheen away from the enterprise. We wouldn't be able to reveal the finale either, which is sure to bring a smile on your face.