We all know how the story goes. Darth Vader kills Obi-Wan Kenobi, who turns into a ghost. Luke Skywalker, with encouragement from Obi-Wan’s ghost, blows up the Death Star, trains to become a Jedi with Yoda, confronts Vader. Luke and Vader fight, above. Vader cuts off Luke’s hand and tells Luke he’s his father. Luke returns to Yoda, talks to Obi-Wan’s ghost, who confirms that yes, Vader is Luke’s father even though he originally told Luke that Vader killed his father. That depends on one’s perspective, Obi-Wan argues.
Again, we all know how the saga plays out. And when it was filmed, so did Luke (Mark Hamill) and, obviously, the guy who actually says “No, I am your father!” (James Earl Jones). And George Lucas, who came up with trilogy and wrote The Empire Strikes Back, well, he also knew that. So did director Irvin Kershner and, if you believe the bonus features on the re-released DVDs, no one else did. Not even the guy in the Darth Vader suit.
As Entertainment Weekly recounts, the surprise twist was not just a surprise to viewers, but also to the cast and crew of Empire itself. But, when David Prowse — the guy in the Vader suit — spoke the lines (before the producers had James Earl Jones dub over them), he didn’t say that Vader was Luke’s father. Instead, per the DVDs, he told Luke that Obi-Wan had killed the elder Skywalker. Hamill was given the true line and was instructed to carry out the scene as if Prowse had said the “I am your father” line, not the one he actually spoke. As the story goes, the rest of the cast and crew found out when the rest of us did — when the film premiered in theaters.
The official story has one flaw — a flaw only Darth Vader himself could conjure. In 1978, a year after the first Star Wars movie but two years before Empire debuted, Prowse appeared at a mostly-overlooked event in Berkeley, California, playing host to about 1,000 fans. Per a newspaper account of the event (via Slashfilm), Prowse “offered the crowd a glimpse of a possible plot for the second sequel [implying this would be in Return of the Jedi, not Empire]. Darth Vader and Luke Skywalker [. . .] are hooked up in a do-or-die lightsaber duel when Luke learns that Darth is, in fact, his long-lost father.”
Which version of film history is the truth is, beyond that, unknown.
From the Archives: London Tube Time Machine: Why did Vader kill Obi-Wan? The bonus fact explains a behind-the-scenes reason.
Related: Quite simply, the best Darth Vader toy ever made.