She is spontaneous, brilliant, the perfect choice...Kajol is undoubtedly one of Karan Johar's favourite actresses and the director says he might not even have made "My Name Is Khan" if she had said no to the film.

"I had only Kajol in mind for Mandira's role. And I don't think I would have made this film had she said no to me. She was the perfect choice for the character. I don't think anyone could have done justice to it as she has," Karan Johar told IANS in an interview.

"Kajol is spontaneous. There is no method to her madness. She is sheer brilliance. Her expressions connect you immediately. She is all real, all woman, all human on screen and I don't think any living actress has the quality that Kajol has," he added.

Releasing Friday, the film is the heart-warming tale of Rizwan Khan (Shah Rukh Khan), who suffers from Asperger's Syndrome (a form of autism), and his journey to win the love of his life Mandira, a single mother.

Asked if he thinks Kajol could portray the character better because she is a mother in real life too, he said: "Yes, she could connect to the character well because she is a mother first, then a wife and then an actress. I think she is, by her own admission, a solid mother and that's how she defines herself," said Karan.

The filmmaker insists the disorder in Shah Rukh's character acts as a texture and an added layer but it's not the focus of the film.

"We needed a character not to be neurotypical because when he is asked to embark on a journey to meet the US president, it's a very illogical demand to make. But it's told to him in the heat of the moment and he takes it to heart," Karan explained.

"If he was neurotypical, like you and I, logic would have played a big part. But he followed the instruction," he added.

Karan believes it is difficult to make pure love stories nowadays because there is bound to be a certain cynicism attached to it.

"I think a pure love story is difficult to make as we used to do decades ago. There is too much cynicism and too much of a grey area surrounding love. That's why a very pure love story will have certain cynicism attached to it. That's my belief. Having said that, I believe that there are some great love stories waiting to be made," said Karan.

It has been reported that Fox STAR is undeterred by the unprecedented success of Rajkumar Hirani's "3 Idiots" and hope to hit the bull's eye with "My Name Is Khan".

Does it pose any challenge to Karan as a filmmaker?

"I don't make a film and predict a business of it. I make a film I believe in. Yes, it's a challenging film because it is a new kind of film - challenging for Shah Rukh because it's a new level of performance for him, challenging for the entire team.

"At the end of the day we have done it with certain conviction, passion and heart and we are very, very confident that the film will connect on a human and emotional level. I don't know how good business will be...I can't predict that...all I can say is that the film is made with a lot of heart, integrity and honesty," Karan said.