Director and producer Aanand L. Rai, who is busy in post-production of his forthcoming film "Zero", says Salman Khan and Shah Rukh Khan never made him realize they are superstars while working as they came together for a special song in the film. He was interacting with media at the trailer launch of "Happy Phirr Bhag Jayegi" along with actors Diana Penty, Sonakshi Sinha, Ali Fazal, Jassi Gill, Aparshakti Khurana, Piyush Mishra, co-producer Krishika Lulla and director Mudassar Aziz on Wednesday.