Since it was announced, The Hobbit has spawned rumors that characters from the original three films would make an appearance despite their not appearing specifically in the original text of J.R.R. Tolkein's novel.
Earlier today, Deadline offered more specific details, indicating that the actors likely to return include Orlando Bloom and Elijah Wood in addition to the more obvious potential casting of Ian McKellen and Andy Serkis (whose characters both play prominent roles in the original story).
UPDATE: Less than 24 hours after Deadline suggested that Elijah Wood would be returning, ComingSoon.net has received confirmation from the actor's reps that Wood will indeed be returning and that he's confirmed to star in the film. They've also informed us that Wood and comedian Eddie Izzard will be starring in the SKY TV mini-series based on Robert Louis Stevenson's literary classic "Treasure Island," playing Ben Gunn. It will be directed by Steve Barron, who directed the original Teenage Mutant Ninja Turtles as well as some of the classic music videos of the '80s including "Video Killed the Radio Star."
Earlier, TheOneRing.net suggested that Wood, at least, is a near certainty and offered some spoilers as to how his appearance is planned to play out, which you can read about by clicking here.
The two Hobbit films are expected to go into production next month.