That Karan Johar has a huge role to play in shaping up the careers of his 'students' Alia Bhatt and Varun Dhawan is a fact known by all. Not only did he launch these talented actors in his 2012 directorial 'Student Of The Year', but he has also guided them all their career journeys and produced last year's hit movie 'Humpty Sharma Ki Dulhania'. Read - Salman Khan out; Varun Dhawan, Alia Bhatt finalised for Karan Johar’s ‘Shuddhi’ The duo has also been roped in to play the mature characters of Shiva and Sati in KJo's magnum opus 'Shuddhi'. Now it's Alia and Varun's turn to do something for their mentor and thereby, they have planned to host a birthday party for the filmmaker. Karan Johar celebrates his 43rd birthday tomorrow (May 25). Read - Salman Khan suggested Varun Dhawan’s name as his replacement in ‘Shuddhi’ KJo is famous for giving lavish birthday parties and with Varun and Alia joining in for the celebration, we're sure it's going to be a grander affair.