James Cameron’s long-gestating Avatar franchise still won’t be anything beyond its record-setting original for another two years, but the four planned sequels to the Na’vi-starring sci-fi hit are still plugging along at their top-secret production pace. In fact, despite previous statements hedging the bet, saying that depending on how the first two Avatar sequels do, the latter pair may or may not happen, Cameron has now revealed that he’s already completed some work on the fourth Avatar.

Speaking to Variety, Cameron and others from the first film talked about the process of creating the groundbreaking original and, more importantly, gave an update on the franchise’s future. The most recent news from Pandora came when the team wrapped production for 2019. But that was assumed to be on the second, water-based film in the series. According to Cameron, it may have been much further down the line.

“From 2013 until now we’ve mostly designed the whole world across four new movies,” the director said. “We’ve written, finished scripts for all four of those films. We’ve cast them, and we’ve [performance] captured movie 2, movie 3, and the first part of movie 4.” Finished scripts? Already working on performance capture for the fourth film? Sounds like either the studio (20th Century Fox, now a division of Disney) has more faith in Cameron than before or the production was so streamlined that it was simple and/or cost-effective to slide right onto the next film.

Principal production on Avatar 2 and Avatar 3 wrapped last year, but pickups, reshoots, and other elements of late-stage production are a necessity for any movie of this scale and VFX complexity. So when Cameron says that “We’re mostly done with the live action,” there’s still lots of work to be done. “People don’t really understand the scope and complexity of the process,” the director explained. “It’s like making two and a half big animated films. A typical big animated film takes about four years, so, if you do the math on that, we’re kind of right on schedule for December 2021.”

So when do things pick up again for the world of Avatar? “I’ve got a couple months in New Zealand in spring,” Cameron said, “so we’re kind of on track with what we set out to do.” New Zealand is where some of the principal photography for the sequels has taken place, so this could mean continuing to finish up the first pair or, since they’ve already begun capturing performances for Avatar 4 (and they have a full script done), looking to the future.

The future of Avatar stars returning faces like Sam Worthington, Zoe Saldana, Sigourney Weaver, and Stephen Lang alongside important newcomers Kate Winslet, Edie Falco, Vin Diesel, Jemaine Clement, and Michelle Yeoh as the new entries to the series make the sci-fi phenomenon into a full-fledged franchise.

It all starts when Avatar 2 continues the story on Dec. 17, 2021.