Filmmaker Karan Johar celebrated his 50th birthday on Wednesday with the who's who of Bollywood. The celebration was hosted in Mumbai's Yash Raj Films Studio. Among those who attended the celebration were actors? Aamir Khan, Hrithik Roshan, Aishwarya Rai, Anushka Sharma, Salman Khan, Gauri Khan, Shanaya Kapoor, Tiger Shroff and others.