You don't have to be a Star Wars superfan to see the first spinoff movie Rogue One: A Star Wars Story, says director Gareth Edwards, but he's hoping the film will light a passion for the franchise in any newcomers.

The first of three planned Disney Star Wars spinoff films, Rogue One is intended as a stand-alone movie, although it is set before the original 1977 film A New Hope.

Anticipation is high with tickets selling fast ahead of the Dec 14 world rollout, and box office analysts are predicting that Rogue One will take in some $130 million at North American movie theaters on its opening weekend.

Rogue One doesn't start with the signature Star Wars theme music or the screen crawl of story information that opened the previous seven films in the franchise.

"You don't have to have seen Star Wars to come and see this film," Edwards says.

"My goal would be, if we do our jobs properly, that by the time the film ends, the first thing you want to do is watch A New Hope and see the rest if you haven't seen it before."

Secrecy has been tight around plot details, but Rogue One will follow a group of rebels led by Jyn Erso (Felicity Jones) who embark on a mission to steal the plans for the Galactic Empire's new super weapon, the Death Star.

Not only is a female character front and center of the action, but the film has one of the most diverse casts yet for a big-budget Hollywood movie, including Mexico's Diego Luna and Chinese actors Jiang Wen and Donnie Yen.

Edwards says the diversity came directly from the plot.

"In our story, the rebellion is fractured and it's before A New Hope ... There's all these other groups from all over the galaxy that are not really getting along and functioning properly.

"So we needed to visually represent that with different ethnicity and all sorts, so it was just a really good opportunity and the second you do that you also go: 'OK, now we can cast anyone in the entire world', so it's amazing," Edwards says.