"I think there can be only one Kareena. I am extremely close to her. I love her for what she is on celluloid and as a person. She has that certain spunk, energy in her. Kareena has a tremendous body of work and has set the bar high and it is not fair to compare (her) with anyone," Karan told reporters at a function here.
There have been comparisons between Kareena and newcomer Alia Bhatt for quite some time.
Alia is playing a Kareena Kapoor fan in Karan's upcoming film 'Humpty Sharma Ki Dulhania'.
In the trailer of the movie launched here, Alia is seen saying to her relatives, "Main shaadi karoongi to Kareena wala designer lehenga pehen kar..' (I will marry wearing the designer lehenga worn by Kareena).
"Alia is new and I am sure she will work hard and go her way up and be known as Alia Bhatt than anyone else," the filmmaker said.
In tune with the title of the film, 'Humpty Sharma..', lead actors Varun and Alia unveiled the trailer with zest and funny act in which Varun came in a 'doli' (palanquin) looking for his bride and Alia coming dancing with revellers.
"It ('Humpty Sharma...') is a filmy love story. We all talk about how our love stories are different. This film is different from '2 States'," Alia said.
Varun and Alia, who made their debut with 'Student Of The Year' are known to share a sizzling chemistry on and off screen. But Alia denied reports of the two of them dating each other.
She was also linked to Arjun Kapoor, her co-star from her latest release '2 States' and now again reports of Varun and Alia are making news.
On her link-ups, Alia said, "What to do May be in my next film, I will be linked to other actor. But there is no truth in it (link-ups)".
The film also starring popular TV actor Siddarth Shukla is releasing on July 11.
Shukla, of 'Balika Vadhu'-fame, thanked producer Karan Johar and director Shashank Khaitan for giving him the break.
"I had a wonderful experience working on the film and it is a big thing to come from TV to films," Shukla said.
Varun revealed on the occasion that Siddharth has more fan following than anyone of them. "He has an incredible fan following among every age group including (among) auntys, kids etc. We are trying to use that for the film," Varun said.