Few cinematic secrets were better kept—or more shocking when they came out—than that of Luke Skywalker and Leia Organa's true parentage in the Star Wars saga. According to ComicBook.com, the reveal that Darth Vader is Luke and Leia's father was such a well-kept secret that it wasn't actually put into the script at all. Evidently, only three people on set knew about the moment in advance: Mark Hamill, Star Wars creator George Lucas, and The Empire Strikes Back director Irvin Kershner. (Screenwriter Lawrence Kasdan was also aware.)

Hamill took to Twitter to explain the pivotal part of the franchise, during which a fake line was used so the actual reveal could be dubbed in afterwards, allowing the trio to keep the secret from the cast and crew for more than a year.

"The cast & crew first learned of it when they saw the finished film," Hamill said to his 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!"

Props to them for not letting the spoiler slip early. Even with the pressure of keeping such a big plot twist under wraps, Lucas says financial concerns were what plagued him most.

“Well, to be very honest, the most challenging aspect was paying for [The Empire Strikes Back],” Lucas recently told StarWars.com. “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.”

If you feel like reminiscing about a galaxy far, far away, check out this year's May the Fourth celebration compilation here. And if you want to see the twist for yourself (whether it's for the first or the hundredth time), all nine movies in the Skywalker Saga are now streaming on Disney+.

[h/t ComicBook.com]

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