Three years later in Paris, Karan is visiting his father Arjun (Rishi Kapoor), when he runs into Rhea. He learns from Rhea's mother Parminder "Bobby" Prakash (Kirron Kher) that Sameer has died in a car accident just after their first marriage anniversary, and he sets out to help her reclaim her positive outlook on life. Karan returns to Mumbai, and three months later, Rhea and Bobby visit. Sensing that she needs to be with a strait-laced, "boring guy," he conspires with Bobby to fix her up with his shy best friend, Mihir Vora (Jimmy Sheirgill). But eventually Mihir falls in love with a friend of Karan's, Diana Fernandez (Isha Koppikar) and they get engaged. On the engagement night, Rhea learns from drunk Diana about the conspiracy and gets upset with Karan. Mihir makes Rhea realize hers and Karan's love for each other. That night Rhea and Karan consummate their relationship. Karan deems it a mistake and asks Rhea to marry him as he feels he took advantage of her, and that marriage will rectify the mistake. Rhea becomes upset, as she did not consider their actions a mistake; she realizes she loves him but tells Karan that they should not commit one more mistake by marrying for the wrong reasons. Rhea leaves him since Karan projects his confused feelings as guilt rather than love for her. Karan realises his mistake and tries to seek her out but fails. One year later Karan's cartoon Hum Tum becomes a hit and he writes a book about Hum and Tum. Basically, the story is based on his love story with Rhea, who reads that book and finds him in the press conference. Karan and Rhea reunite again. Karan admits his love for her, and they get married and have a baby girl. Cast Saif Ali Khan as Karan Kapoor Rani Mukherji as Rhea Prakash Rishi Kapoor as Arjun Kapoor, Karan's father Kirron Kher as Parminder "Bobby" Prakash, Rhea's mother Rati Agnihotri as Anjali "Anju" Kapoor, Karan's mother Jimmy Sheirgill as Mihir Vora, Karan's friend Isha Koppikar in a cameo appearance as Diana Fernandez, Mihir's love interest Abhishek Bachchan in a special appearance as Sameer Khanna Shenaz Treasurywala in a special appearance as Shalini Gupta Parinita Seth as Pooja Gupta Parzaan Dastur as the voice of Hum Gayatri S. Iyer as the voice of Tum Production Aamir Khan was first approached for the role