"Star Wars: The Force Awakens" has seen a big marketing push from Disney and LucasFilm, from trailers to toys and major conventions. However, there is still a lot of secrecy surrounding the film such as any plot point regarding Luke Skywalker (Mark Hamill) and Supreme Leader Snoke (Andy Serkis).

Director J.J. Abrams discussed the reason for such secrecy on "Good Morning America" (via The Hollywood Reporter). The director pointed out that he didn't want to ruin the movie for the audience and that it was important for the people involved in making the film that they didn't give too many details away and to avoid overselling the film.

A part of the secrecy, as mentioned, is Luke Skywalker. Skywalker has been identified as the main hero of the franchise; however, he has not been seen in any of the posters or toys and his only appearance in any of the trailers is a quick shot of him with R2-D2 but his face is covered and there are rumors that it might not even be him.

This has led to speculations of Luke Skywalker being a villain or perhaps a character in hiding. His appearance may also be a major clue in discerning certain plots in the movie, which is possibly why he is being kept away from promotional materials.

Speaking on the "Howard Stern Show," Abrams revealed that this mystery surrounding Skywalker was partly why he agreed to direct the film despite his earlier reluctance to take on the job.

He points out that the events of the original "Star Wars" trilogy occurred decades ago and that the newer characters, such as John Boyega's Finn and Daisy Ridley's Rey, might not even have heard of them.

"The thing that grabbed me was that feeling of a new, young character... asking 'who is Luke Skywalker?' And I don't know why, but [expletive] that's so cool. The idea that there would be a discovery, these would be kids who didn't see Star Wars themselves, but would be in this universe."

"Star Wars: The Force Awakens" opens this Dec. 18.