Star Wars composer John Williams didn't know Luke and Leia were siblings when he was scoring the first movie – and to be fair, we're pretty sure George Lucas didn't know either.
"I mistakenly wrote a love theme for Princess Leia and Luke Skywalker," Williams told Variety. "I learned later that they were brother and sister, so it was an incestuous idea to have a love theme for them. But George never told us there was going to be a second film!"
Considering that Leia quite literally kisses Luke on the lips at one point in the flagship film, we understand the confusion. George Lucas later revealed in the book Star Wars: The Annotated Screenplays that making them siblings would be motivation enough for Luke to battle Darth Vader in Return of the Jedi's infamous 'Throne Room' scene (H/T ScreenRant).
