After 40 years, it's still unclear why a Wampa attacked Luke Skywalker at the beginning of "Star Wars: The Empire Strikes Back."

One theory is that it was added to prepare fans for how Mark Hamill looked compared to "Star Wars: A New Hope."

Before "The Empire Strikes Back" began filming, Hamill was in a car accident that fractured his nose and left cheekbone.

The Wampa mauling Skywalker's face may have been a way to explain Hamill's appearance.

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On January 11, 1977, Mark Hamill got into a car accident that fractured his nose and left cheekbone.

If the accident had happened four months later, the news would have been in every paper around the world. But at the time, Hamill was still an unknown actor who had just finished being the lead in a yet-to-be-released sci-fi movie in which he wore all white and wielded a glowing sword.

Hamill had to have cartilage taken from his ear to rebuild his nose.

But when "Star Wars: A New Hope" opened on May 25, 1977, breaking box office records and making everyone involved — especially Hamill as Luke Skywalker — overnight sensations, little attention was made about Hamill's accident.

However when the sequel to "A New Hope," 1980's "The Empire Strikes Back," opened with Skywalker being mauled in the face by a Wampa, fans speculated that the scene was written because Hamill's face looked different after his accident.

The rumor has become one of the biggest unsolved mysteries of the "Star Wars" saga, 40 years after the film was released.

Mark Hamill got in an accident after filming 'A New Hope'

Speaking to Gossip Magazine in 1978 for the release of "Corvette Summer," which was released between "A New Hope" and "The Empire Strikes Back," Hamill spoke about the accident.

"What happened was that I was on the wrong freeway," Hamill said. "I was way out in the sticks somewhere and there were no cars and no traffic, thank God. I was going about 65-70 mph... I was speeding, going too fast... and what happened, I think, was that I tried to negotiate an off-ramp and lost control, tumbled over, and went off the road. I fractured my nose and my cheek."

(L-R) Mark Hamill in "A New Hope" and "The Empire Strikes Back." Lucasfilm

Hamill also said in the interview that the next day he was supposed to do pick-up shots for "A New Hope" of scenes on Tatooine. This led to director George Lucas having to use a double, though the shots were for scenes where you wouldn't see Hamill's face.

So Hamill's accident did not affect the completion of "A New Hope," but the question is, did it alter "The Empire Strikes Back?"

George Lucas says the Wampa scene wasn't written to explain Hamill's appearance in 'The Empire Strikes Back,' but it helped

This is where the story gets hazy.

In the opening scene of "The Empire Strikes Back," Skywalker's face is scratched after being attacked by a Wampa, which digs its claws into his face and then drags Skywalker and his Tauntaun back to its cave. George Lucas says the Wampa scene helped justify Hamill's new look to viewers, but suggests the scene wasn't written because of his accident.

"At the end of 'A New Hope' he had been in a car accident and I knew Mark was going to look a little different than he was in the first film," said Lucas in the Blu-ray commentary of "The Empire Strikes Back."

"But my feeling was some time had past, they've been in the Rebellion fighting, that kind of thing, so the change was justifiable. There's a scene in the film where Mark gets beat up by the monster [Wampa], which helps even more, but that wasn't really the meaning of why we wrote the monster in the beginning. We needed something to keep the film suspenseful at the beginning while the Empire is looking for them."

However, Carrie Fisher, who played Princess Leia, remembers things differently

A shot of Luke Skywalker's face being attended to that was cut out of the film. Lucasfilm

"I was still shooting 'Star Wars' when Mark got into the car accident," Fisher said in the commentary. "It was a really bad accident. Miraculously his teeth didn't shatter. But his nose did. He had to have some of his ear put into his nose. So they adjusted the film with this snow monster to right away in the movie scratch his face to account for his looks being different."

Revealed in the book, "The Making of Star Wars: The Empire Strikes Back," a scene was filmed after Skywalker is saved from the Wampa attack where his damaged face is attended by a droid (see photo above).

That portion was cut out, though it seems clear Lucas and "Empire" director Irvin Kershner were working out how far they wanted to go to address Hamill's restructured face.

Mark Hamill has been quiet about the whole thing through the years, but said the makeup department built on his real scars for his film appearance

For the most part Hamill has been quiet about the origin of the Wampa scene, but this interview with the actor posted on YouTube in 2014 does indicate that the make-up department on "Empire" did play on his scars from the crash.

Briefly describing what he remembers from the accident, he then said: "they used a lot of the real scars to build upon" the make up used for the scene.

This is not Hamill admitting that the Wampa scene was written due to how his face looked after the accident, but it's interesting to hear that his scars from the crash were on the mind of the make-up department.

Watch the Wampa attack scene, followed by Skywalker escaping the Wampa's cave in the version that showed in theaters when "The Empire Strikes Back" was released 40 years ago: