Aamir Khan, Alia Bhatt, Malaika Arora Khan, Vidya Balan, Hrithik Roshan, Huma Qureshi, Kangna Ranaut, Sidharth Malhotra, Varun Dhawan, Sonakshi Sinha, Bipasha Basu, Harman Baweja and many other Bollywood stars graced the 42nd birthday bash of Karan Johar in Mumbai. Must watch!