After over thirty years away from their roles in the original "Star Wars" trilogy, no one could really blame returning actors Carrie Fisher, Mark Hamill and Harrison Ford if it took them a while to rediscover their characters on the set of "Star Wars: The Force Awakens." J.J. Abrams, the director behind the first new "Star Wars" film since the 2005 prequel "Revenge of the Sith," revealed that he felt that very doubt in a new interview with the Associated Press -- but, as Abrams revealed, he had to reason to worry.

"What was incredible from my point of view was how apparently easily they flipped back into these roles," said Abrams of the new film's veteran actors, which also includes Peter Mayhew (Chewbacca), Anthony Daniels (C-3PO) and Kenny Baker (R2-D2). "I knew for a fact, for example, that Harrison Ford was going to be in this movie, but I couldn't be certain that Han Solo would be. Meaning, I hadn't seen Han Solo return after nearly 40 years, either. And it wasn't until we got on set that I got my answer. It was a remarkable thing to see how effortlessly Harrison Ford became Han Solo again."

Being on set with so many film icons proposed a different kind of obstacle for the director, where joyful nostalgia threatened to overshadow the task at hand. "That was a constant in the production of the movie: moments where we would all look around and realize what we were doing and gasp a little bit and then dive back in," said Abrams. "When you're on the set of the Millennium Falcon or staring into the eyes of C3PO giving direction, it's pretty easy to have that fanatic part of you bubble up. But our job was to be there to tell this story, not to be a fanboy."

"Star Wars: The Force Awakens" opens on December 18, 2015.