He says he can "no longer can be friends" with cigarettes, which he once called his "best friend".
"I thought you were my best, coolest friend and I wanted you all the time, but the payback you ask for is immense and we can no longer be friends. #quitsmoking"," Sushant tweeted.
Meanwhile, he's gearing up for the upcoming film "M.S. Dhoni: The Untold Story", in which he will essay India's World Cup-winning captain Mahendra Singh Dhoni. The Neeraj Pandey directorial will hit the screens on September 2.