James Cameron’s “Avatar” sequels have been delayed again due to plans of making the four follow-up films simultaneously.

“Well, 2018 is not happening,” Cameron told The Star. “We haven’t announced a firm release date. What people have to understand is that this is a cadence of releases. So we’re not making ‘Avatar 2.’ We’re making ‘Avatar 2, 3, 4 and 5.’ It’s an epic undertaking. It’s not unlike building the Three Gorges dam. So I know where I’m going to be for the next eight years of my life.”

In January 2016, TheWrap exclusively reported that “Avatar 2,” the first of three sequels to Cameron‘s 2009 3D sci-fi blockbuster, would not be ready in time for its planned Christmas 2017 release. That was already the second delay for “Avatar 2,” which Fox had originally planned to release by Christmas of 2016.

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“Avatar 2” was scheduled for December 2018, with the sequels arriving in 2020, 2022 and 2023. Cameron announced the plans for four sequels in 2016.

“It’s not an unreasonable time frame if you think about it,” added Cameron about the next eight years. “It took us four-and-a-half years to make one movie and now we’re making four. We’re full tilt boogie right now. This is my day job and pretty soon we’ll be 24-7. We’re pretty well designed on all our creatures and sets. It’s pretty exciting stuff. I wish I could share with the world. But we have to preserve a certain amount of showmanship and we’re going to draw that curtain when the time is right.”

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

“Avatar” remains the highest-grossing movie of all time worldwide, having earned $2.8 billion since its release in 2009, though “Star Wars: The Force Awakens” did dethrone “Avatar” from its record-breaking top spot domestically.

Fox has not yet responded to TheWrap’s request for comment.