Thousands of sci-fi fans invaded the Los Angeles Convention Centre Wednesday for the biggest Star Wars party ever to celebrate the birthday of the most successful movie franchise in history, which debuted in just 32 movie theatres on May 25, 1977.

For the first-ever consecutive US screening of all six Star Wars films, the 17-hour marathon is to open the event for the five-day official 30th anniversary Star Wars convention, which is expected to draw 35,000 fans.

"It's quite simply the biggest and best Star Wars event ever," said Steve Sansweet, the head of fan relations for Lucasfilm.

The convention will also include speeches and autograph sessions by many of the stars, as well as costume events, a vast dealers' floor piled high with memorabilia and collectibles, arts and activities for kids.

Star Wars was an immediate hit, "appealing to people at a time when things maybe weren't going great," said Anthony Daniels, who played C-3PO in six movies and several TV specials. "People wanted something to make them feel good, and boy, did it take them out of their environment."

The movie went on to earn 460 million dollars at the US box office, spawning five sequels that took in over 20 billion dollars worldwide.
"There's no question that the film made the entire movie industry rethink its attitude toward summer movies, toward juvenile movies for big kids, science fiction, special effects and, of course, merchandising," film historian Leonard Maltin said.

"In that era, before the birth of home video, the only way to see a movie again was to go back and pay your admission at the theatre," Maltin said. "And people did, over and over again."