PHOTOS: Hrithik Roshan, Varun Dhawan and girlfriend Natasha attend Karan Johar's birthday bash

Karan Johar just rang his 45th birthday and is currently throwing the biggest party B-town has probably ever seen. The who's who of Bollywood has headed for this grand bash and seen here is the hot and handsome Hrithik Roshan. 

Also seen is Varun Dhawan, who came with girlfriend Natasha Dalal. Varun, who debuted in Bollywood with KJO's Student of the Year, was last seen in Karan's movie Badrinath Ki Dulhania opposite Alia Bhatt. The movie was a hit at the BO.

Varun recently took to his social networking handle to wish his mentor. He wrote, "Happy birthday @karanjohar. Wish you many more smiles ahead. Your the best person I know thank you for being you."

On the work front, Varun just wrapped the London schedule of his film Judwaa 2, which is a remake of the 1997 Salman Khan movie Judwaa. The movie is helmed by his dad David Dhawan and stars Jacqueline Fernandez and Taapsee Pannu.

Others who attended the grand bash today are Deepika Padukone, Ranbir Kapoor, Katrina Kaif, Aishwarya Rai Bachchan, Sidharth Malhotra, Alia Bhatt, Aditya Roy Kapur, Sara Ali Khan, Disha Patani, Sushant Singh Rajput and Kriti Sanon among others.

Sure looks like a lot of fun, doesn't it?