After working with the likes of Kajol, Kareena Kapoor, Rani Mukherjee and Preity Zinta, Karan Johar is now finding himself in an unfamiliar zone, what with a rank newcomer Alia Bhatt being his leading girl in 'Student of the Year'.

While it was a conscious decision on Karan's part to experiment with new, untried and untested talent for his campus flick, there was quite some challenge that he had lined up for him when he started scouting for the actors.

"For the film's heroine, we had actually screen tested over 400 girls from across Mumbai as well as other cities.

This is when my writer Niranjan Iyengar told me that Mahesh Bhatt's daughter Alia was raring to go and she could just be the right fit for the film. I did her test and was convinced that she had this X factor that could work for the film", says Karan.

"Also, what worked in her favour was that I could see a quintessentially mainstream yet different leading girl in her", he adds.

Well, if the song-n-dance routine so far is anything to go by, seems like the combination has really worked well for Karan and his film.

With Rishi Kapoor in the role of a Dean, 'Student of the Year' has music by Vishal-Shekhar and releases all over on 19th October.