Star Wars Day is May 4, when fans of the films greet each other with the words "May the fourth be with you".
The line 'May the fourth be with you' was actually first seen in a newspaper headline greeting Margaret Thatcher's election as UK Prime Minister on May 4, 1979.
The first official Star Wars Day delebration was in 2011 in Toronto, Canada, though Los Angeles City Council had declared May 25 to be Star Wars Day, 34 years earlier in 1977.
May 25 was later expanded into Geek Pride Day, adding the works of authors Douglas Adams and Terry Pratchett to the celebrations.
In early drafts of the first Star Wars film, Luke Skywalker was called Luke Skykiller.
In 1996, 37 per cent of the toys sold in the USA are said to have been Star Wars products.
In one scene of The Empire Strikes Back, one of the deadly asteroids is actually a potato.
The total box office revenue generated by the Star Wars films is around $5.5billion (£3.4billion).
The only series that have made more money are the James Bond films and the Harry Potter films.
Denis Lawson, who plays Wedge Antilles in Star Wars IV, V and VI, has his first name misspelt as 'Dennis' in the credits of the first two of those.