Star Wars: Mark Hamill Reminds Fans Of Major Empire Strikes Back Filming Detail We Almost Forgot

There are few cinematic moments more surprising than when Darth Vader revealed he was the father [...]

There are few cinematic moments more surprising than when Darth Vader revealed he was the father of Luke Skywalker (Mark Hamill). Take a pause and think about it; which moments in the annals of pop culture history are more surprising? In fact, the moment was so big that it wasn't put into the script. In fact, only three people ever knew about the moment: Hamill, Star Wars architect George Lucas, and Empire director Irvin Kershner. As Hamill reminded people Sunday afternoon, it was so secret, the three eventually dubbed the moment in later so the rest of the cast and crew couldn't find out.

Hamill tells his Twitter following he, Lucas, and Kershner all kept the moment secret for over a year until Empire in 1980. "The cast & crew first learned of it when they saw the finished film," Hamill reminded fans on Twitter. "When we shot it, Vader's line was 'You don't know the truth, Obi-Wan killed your father.' Only Irvin Kershner, George Lucas & I knew what would be dubbed in later. Agony keeping that secret for over a year!"

The fan-favorite flick debuted 40 years ago this week and Lucas caught up with earlier this week for the anniversary. Even after the original Star Wars burst onto the scene several years earlier, Lucas says securing the funding for a sequel might have been the most challenging part of the entire production process.

"Well, to be very honest, the most challenging aspect was paying for it," Lucas says now. "In order to be able to take control of the movie, I had to pay for it myself. And in order to do that, I did something my father told me never to do, which was to borrow money. But there wasn't much I could do because I only had maybe half of the money to make the movie so I had to borrow the other half, which put a lot of pressure on me."

"I was learning…I don't like writing," Lucas added. "In this case, Leigh Brackett died literally the day she turned the first draft of the script in and it wasn't really much like I had expected or wanted and so I was stuck. I had been working with [screenwriter] Larry Kasdan on Raiders [of the Lost Ark] but he wasn't finished yet." Lucas went on to ask Kasdan if he'd tackle a third version of the Empire script with Lucas taking on big plot points in draft number two. "And he said, 'How do you know I'm a good writer?'" Lucas remembered. "And I said, 'Well, when you turn in the script, if it's no good then the deal's off." Lucas worked on the second draft "and then while I was reading Raiders, he was writing Empire."

Star Wars: The Empire Strikes Back is now streaming on Disney+.