Here are 10 things only a true Star Wars fan would know - May the Fourth be with you.
1.Harrison Ford and Mark Hamill generally played the fool on set while filming the first film. They only behaved when senior actor Sir Alec Guinness was around.
2.When Harrison Ford found out that Darth Vader was Luke Skywalker's father he said: "I didn't know that. Why the ?#@*!$ didn't you tell me?"
3.R2-D2 and C3PO appear as hieroglyphics in a scene in Raiders Of The Lost Ark (also starring Harrison Ford).
4. Han Solo is the only non-Jedi who gets to use a light saber, when he cut open the tauntaun's stomach to keep Luke warm. But he doesn't get his own, he uses Luke's.
5. The gold bikini Carrie Fisher wore as Princess Leia in Return Of The Jedi was a result of the costumes she wore in the first two movies in which, she complained, no one could tell "she was a woman.'
6. Scientists have actually calculated what it would take to build a real Death Star. They concluded that it was possible in theory but would require too much time and money.
7. By the third film, Anthony Daniels was able to get into his C3PO costume in minutes rather than hours.
8. Jabba The Hutt was six people in an animatronic suit.
9. David Prowse and James Earl Jones, the body and voice of Darth Vader, never actually met.
10. Ewan McGregor, who took over from Sir Alec Guinness as the young Obi Wan-Kenobi in the prequel trilogy, made light saber 'noises' all through filming the fights in The Phantom Menace which had to be deleted in post-production. Adam Driver, who joins the new cast in Episode VII, said he wanted to make light saber and R2-D2 noises on set but didn't.