Adam Driver feared he would be fired from Star Wars: The Force Awakens on day one after "swinging blind" in a fight scene with movie icon Max von Sydow.

The Marriage Story actor made his debut as Kylo Ren in the 2015 movie, and his first job during filming at London's Pinewood Studios was to attack von Sydow's Lor San Tekka in one of the opening scenes of the movie.

However, the Girls star worried he would cause serious injury to the veteran, who was 85 at the time, because he could barely see out of his character's iconic black and sliver mask.

"My first thing I had to do was kill Max von Sydow (onscreen)," he recalled to Rolling Stone magazine. "I have this long saber, and I can't see where it's going. So I didn't want to, on my first day, just whack Max von Sydow. That would be the end of the movie, for me."

Von Sydow survived unscathed, but Driver insisted his lightsaber skills had nothing to do with it: "I missed him - but it was total luck, because I was kind of swinging blind."

Driver has since reprised his role for 2017's The Last Jedi and the upcoming The Rise of Skywalker, but despite continued fight training, he still doesn't feel like he's mastered the sword.

Speaking before recently celebrating his 36th birthday, he shared, "The great thing about acting is you never figure anything out... I'm 35, and I still don't know anything about anything."

Driver has had a stellar year, with other film credits including The Dead Don't Die and The Report, and he admitted he's waiting for the bubble to burst on his success.

"I often think that there's someone hanging in the sidelines with, like, a big fly swatter," he shared. "I'm waiting for reality to hit."

Star Wars: The Rise of Skywalker hits cinemas from 18 December.