Joseph Gordon-Levitt joins "Inception"

LOS ANGELES (Hollywood Reporter) - Joseph Gordon-Levitt is signing on for "Dark Knight" director Christopher Nolan's "Inception," a thriller starring Leonardo DiCaprio.

The story line of the Warner Bros. project, which Nolan also wrote, remains rapped in a veil of secrecy, with no details announced beyond the description that it's a contemporary sci-fi action tale set within "the architecture of the mind."

Gordon-Levitt is taking the role that was to have been played by James Franco, who bowed out over scheduling issues. He would play an associate of DiCaprio's character, a CEO-type.

Marion Cotillard is already on board as DiCaprio's wife, while Ellen Page is playing a grad student and DiCaprio's sidekick. Cillian Murphy is also in the cast.

Nolan and the studio are aiming for a summer shoot and a 2010 release.

Gordon-Levitt ("The Lookout," "Mysterious Skin") has a big summer lined up: He stars in the romantic comedy "500 Days of Summer," opening in July, and plays the villainous Cobra Commander in "G.I. Joe: The Rise of Cobra," which opens August 7.

(Editing by Sheri Linden at Reuters)