'Bones': Michael Clarke Duncan joins potential spin-off

The proposed "Bones" spin-off may not have a lead yet -- but it does have bragging rights to one heck of a supporting player.

Michael Clarke Duncan, star of "The Green Mile" and one of the smiley-est faces in Hollywood, is the first actor on board.

First reported by Deadline and confirmed by FOX, Duncan will play Leo, the partner to title character Walter Sherman, "The Locator."

Leo is described in the books -- on which the pilot is based -- as tough, philosophical cowboy type.

He'll be introduced, along with the rest of the pilot's cast, in the episode 19 of "Bones" current season. Filming is expected to start later this winter.

Should "The Locator" go to series, it will be Academy Award-nominated Duncan's first regular TV gig.