“Avatar 2,” the first of three sequels to director James Cameron‘s 2009 3D sci-fi blockbuster, will not be ready in time for its planned Christmas 2017 release via Twentieth Century Fox.

The studio on Thursday declined comment on the delay, which individuals with knowledge of the situation confirmed. There is no new release date set for the movie, or word on the two other sequels, which Fox had planned to release in the same holiday corridor in 2018 and 2019.

It’s the second delay for “Avatar 2,” which Fox had originally planned to release by Christmas of this year. Cameron intends to shoot all three films in the trilogy at the same time in New Zealand, with Cameron and Jon Landau producing through Lightstorm Entertainment. Soundstage construction and some computer animation work is in the early stages, but a start date for filming has not been set.

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Leads Sam Worthington and Zoe Saldana in 2014 signed on for the trilogy, which is expected to pick up where the original left off, though Cameron has indicated much of it may be set on a moon of the planet Pandora and underwater.

It’s telling that the studio has never penciled in an official release date for “Avatar 2.” But as recently as last month, Cameron said a 2017 release was on track, and Fox chairman-CEO Jim Gianopulos said the same last summer after visiting the director in his offices in New Zealand.

The Fox chief executive qualified his statement at the time, saying, “James Cameron has his own pace.”

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Another tipoff that the plan to release “Avatar” at Christmas 2017 was in jeopardy came Wednesday, when Disney shifted “Star Wars: Episode VIII” to Dec. 15, 2017.

It’s hard to imagine Disney CEO Robert Iger and “Star Wars” producers Kathleen Kennedy would shift their movie to that date, and re-calibrate the massive Disney marketing machine, unless they were virtually certain they’d have the season — and the pick of IMAX screens — to themselves.

“The Force Awakens” is currently No. 3 on the list of all-time top-grossing films globally with $1.9 billion, behind Cameron’s “Titanic” at $2.2 billion and “Avatar” at $2.8 billion. With both multiple sequels in both franchises on the way, Disney and Fox and their blockbusters should be going head-to-head for the next several years.

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The director is known for being a perfectionist and an advocate of developing new technology to advance the craft, both traits that could potentially delay the process.

The delay could be caused by the underwater element, which is notoriously tricky and often expensive. It’s likely Cameron has been developing envelope-pushing camera equipment for the films as well. The original film took five years to make it to the screen and spent more than two years in postproduction.