Fox

The writing process for James Cameron‘s “Avatar” sequels is so “involved” that he has had to push the release date for the first back to late 2017.

The Associated Press reports the Academy Award winner behind “Titanic” and “The Terminator” dropped the bad news for fans hoping to see the first of three new movies in 2016 while promoting the local film industry in Wellington, New Zealand with “Hobbit” director Peter Jackson. Cameron filmed the 2009 blockbuster there, and has returned to produce the three sequels, which will be released over three consecutive years.

See photos: Disney Releases First Look at ‘Avatar’ Theme Park

“There’s a layer of complexity in getting the story to work as a saga across three films that you don’t get when you’re making a stand-alone film,” he said on Wednesday. “We’re writing three simultaneously. And we’ve done that so that everything tracks throughout the three films. We’re not just going to do one and then make up another one and another one after that.”

Cameron’s writing team includes “Terminator: The Sarah Connor Chronicles” creator Josh Friedman, Rick Jaffa and Amanda Silver (“Rise of the Planet of the Apes”), as well as Shane Salerno, who previously worked with Cameron on “Fantastic Voyage.”

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Both Sam Worthington and Zoe Saldana are expected to return to star in the film, along with Sigourney Weaver and Stephen Lang. On the production side, Joe Letteri and his WETA Digital have also returned to help Cameron expand the world of fictional exoplanetary moon Pandora.

“We’ve designed all the creatures and the environments,” Cameron said.

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“Avatar” became the highest-grossing movie in box office history when it was released six years ago. The 20th Century Fox movie, produced by Cameron’s Lightstorm Entertainment, took home nearly $2.8 billion worldwide in theaters before becoming the highest-selling Blu-ray disc of all time, too.

19 of the Most Loved or Hated Movies: Films That Got A+ or F CinemaScores (Photos)

Nominated for Best Picture and Best Actor at the 87th Academy Awards, "American Sniper" snagged an A+ rating in January 2015.
Warner Bros. Pictures
"42" tells the inspiring tale of Jackie Robinson breaking down baseball's race barriers, a well-deserved A+ recipient in April 2013.
Warner Bros. Pictures
The presence of Brad Pitt and James Gandolfini didn't keep audiences from giving crime drama "Killing The Softly" an F in November 2012.
The Weinstein Company
A star-studded cast and plenty of action elevated blockbuster "Marvel's The Avengers" to an A+ rating in May 2012.
Marvel Studios
Ben Affleck's "Argo" received an A+ in October 2012 from opening night audiences and months later it won the Best Picture Oscar.
Warner Bros. Pictures
"The Help," told through the point of view of maids who worked for white families, obtained an A+ in August 2011.
Walt Disney Studios
Audiences loved the animated movie "Tangled," earning it an A+ in November 2010.
Walt Disney Studios
"The King's Speech" was another Best Picture Oscar winner that audiences knew was a winner, giving it an A+ in September 2010.
The Weinstein Company
"The Blind Side," featuring Sandra Bullock, touched audiences everywhere in November 2009. The semi-biographical sports drama snagged an A+ rating.
Warner Bros. Pictures
James Marsden and Cameron Diaz found a bizarre package in November 2009's "The Box." Audiences found it bizarre enough to give it an F.
Warner Bros. Pictures
"I Know Who Killed Me" starring Lindsay Lohan was not as adored as "Mean Girls." The psychological thriller gave it an F in July 2007.
TriStar Pictures
"Bug" is among several horror movies that drew an F grade in May 2007 from first-night attendees, despite Ashley Judd and Michael Shannon in the cast.
Lionsgate
Aussie backpackers fell prey to murderous bushman in December 2005's "Wolf Creek." Audiences went after it like a dingo, and gave it an F.
Roadshow Entertainment
"The Lord of the Rings: The Return of the King" was a hit with fans, boasting an A+ rating since December 2003.
New Line Cinema
Audiences spaced out on Steven Soderbergh's November 2002 flick "Solaris," and gave the George Clooney sci-fi film an F.
20th Century Fox
Richard Gere, Helen Hunt and Farrah Fawcett couldn't save "Dr. T and the Women" from a F rating in October 2000.
Artisan Entertainment
Denzel Washington and an inspiring tale of race relations added up to an A+ for "Remember the Titans" in September 2000.
Buena Vista Pictures
"Driving Miss Daisy," with Jessica Tandy and Morgan Freeman in the December 1989 flick, was another A+ movie that went on to win the Best Picture Oscar.
Warner Bros. Pictures
Darren Aronofsky's "Mother" starring then-girlfriend Jennifer Lawrence confounded audiences -- and many critics -- and earned an F CinemaScore in September 2017.
Paramount
If you're curious, click on to see all the movies that have flunked in the CinemaScore survey.

Also Read: All 19 Movies That Flunked CinemaScore With F Grade, From ‘Solaris’ to ‘mother!’ (Photos)