In early drafts of the screenplay, writer Leigh Brackett actually had Luke’s father appear to him as a ghost as a separate character from Vader, which was scrapped in subsequent drafts written by Lucas and screenwriter Lawrence Kasdan.

When asked to recount his first meeting with George Lucas, R2-D2 builder Tony Dyson (who passed away in March 2016) said that what they talked about wasn’t R2-D2, but hamburgers and flying. Specifically, “The fact that it's difficult to find a good U.S.-style burger in the UK and how much George dislikes flying. The next meeting we discussed R2-D2 and his fabrication.”

Dutch and German speakers should have known Darth Vader was Luke’s father from the get-go, as the Dutch and German words for father are vader and Vater, respectively.

Much has been made of the lengths to which Lucas and his fellow filmmakers went to keep the revelation that (spoiler alert?) Darth Vader is Luke Skywalker’s father under wraps. In a 2004 interview with Sound & Vision, Hamill shared that “it was a wonderfully hard secret to keep because [Irvin] Kershner, the director, brought me aside and said ‘Now I know this, and George knows this, and now you're going to know this, but if you tell anybody, and that means Carrie or Harrison, or anybody, we're going to know who it is because we know who knows.’” But the truth is that anyone who picked up the novelization of the movie, which was released a month earlier than the film, would have known the plot twist already. (Good thing Twitter didn’t exist.)

Two years before the Empire novelization hit bookstore shelves, a crowd of approximately 1000 Star Wars fans gathered in Berkeley, California to shake hands with David Prowse, the man in Darth Vader’s suit. Believe it or not, Prowse shared that critical plot point with the crowd. A newspaper clipping from 1978 teased the genetic connection, even quoting Prowse as saying, “Father can’t kill son, son can’t kill father.”