The Inception star, who was recently confirmed for an undisclosed role in The Dark Knight Rises, claimed that the film could be the most important project of his acting career so far.
"I feel now, doing Looper, is the result of what happened with Inception," Gordon-Levitt said, according to The AP.
"It is something I have been working on for my whole life," the actor added.
Gordon-Levitt will star in the Rian Johnson-directed project opposite the likes of Bruce Willis, Emily Blunt, and Chinese actress Xu Qing.
Although few details about the film have been released, it will reportedly see both Gordon-Levitt and Willis portray the same character but at different points in time, and will also involve time travel.
Looper will be released in 2012.