EXCLUSIVE: James Cameron and 20th Century Fox have upped the number of Avatar sequels they’ll make from two to three, and they’ve set three high-level screenwriters (one is a team) to get the movies in shape to be shot simultaneously. That is easily a recipe for the most expensive set of pictures ever made, and an ambitious production plan not seen since New Line and Peter Jackson made three The Lord Of The Rings films back to back. Back then, Jackson was coming off The Frighteners. Fox at least has the confidence of knowing Cameron’s last two films are the biggest-grossing pictures in movie history, with Avatar at the top by a wide margin. It’s still a gutsy play; it is not unimaginable that three Avatar installments could cost close to $1 billion. The original grossed $2.8 billion.

Cameron has set War Of The Worlds scribe Josh Friedman to write one film; Rise Of Planet Of The Apes‘ Rick Jaffa & Amanda Silver to write another; with the third to be written by Shane Salerno, who wrote and directed the upcoming documentary Salinger and who previously worked with Cameron on a remake of Fantastic Voyage at Fox. The writers will collaborate with Cameron separately and co-write three separate movies with him.

The three pictures will be filmed simultaneously with production beginning next year. The release of the first sequel will be in December 2016, with the second to follow in December 2017, and the third a year later. Avatar 2, 3, and 4 will be produced by Cameron and Jon Landau through their Lightstorm Entertainment banner. Lightstorm will work once again with Joe Letteri and his team at WETA Digital on the three films.

The choice of writers came after Cameron and Landau spent weeks meeting with A-list screenwriters vying for the job. They’ve been working with Cameron from his Manhattan Beach studio.

Commented Cameron: “Building upon the world we created with Avatar has been a rare and incredibly rewarding experience. In writing the new films, I’ve come to realize that Avatar’s world, story and characters have become even richer than I anticipated, and it became apparent that two films would not be enough to capture everything I wanted to put on screen. And to help me continue to expand this universe, I’m pleased to bring aboard Amanda, Rick, Shane and Josh — all writers I’ve long admired –­ to join me in completing the films screenplays.”

This is far and away the beach head project for 20th Century Fox chairman and CEO Jim Gianopulos, who pulled Cameron out of a proposed plan to direct Cleopatra at Sony with Angelina Jolie, and instead made a deal that ensured his focus would be on expanding his Avatar universe and the groundbreaking 3D technology that brought it to life. The move by Gianopulos kept Cameron in the Fox fold, a relationship that spans nearly 30 years, starting with 1985’s Aliens. Said Gianopulos: “We at the studio have no higher priority, and can feel no greater joy, than enabling Jim to continue and expand his vision of the world of Avatar. The growing breadth and scale of Jim Cameron’s plans for his magnificent fantasy worlds continue to amaze us all.”

Cameron wrote Avatar from an idea he nurtured over a decade, including the technology required to make it happen in immersive 3D, which Cameron accomplished working with WETA Digital. That explained the long absence he took after helming Best Picture Oscar winner Titanic, which was co-financed by Fox and Paramount. Aside from being the all-time biggest grosser, Avatar is also the biggest selling Blu-ray disc ever. It got nine Oscar nominations and won three.