"My friend Raj Kanwarji passed away. The impermanence of life, makes one feel so helpless. May his soul rest in peace. Aisi Deewangi..miss u sir," the superstar tweeted.
Filmmaker Bhushan Kumar, too, confirmed the news, saying: "Yes, it is true that Raj Kanwar is no more. I am really sad about it."
Kanwar, who was in his early 50s, had gone to Singapore for a kidney transplant but he died before the surgery, trade analyst Komal Nahta posted on his website.
Kanwar was the one who gave Shah Rukh and Priyanka Chopra their first big breaks in the film industry with "Deewana" and "Andaaz" respectively. He also directed "Judaai", "Jeet", "Badal" and "Laadla".
His last film was "Sadiyaan" starring Rishi Kapoor, Hema Malini and Rekha. It was also the launch pad for Shatrughan Sinha's son Luv as an actor.