Director James Cameron and 20th Century Fox announced today that Avatar will have three sequels instead of two.

The director of the original Avatar said that while working on the screenplay he realized that the world of Avatar and its characters are way bigger and richer than what he had imagined and hence requires an additional sequel.

Due to the expansion of the project, Cameron has recruited a team of screenwriters to collaborate with him on the three blockbusters: Josh Friedman (War of the Worlds). Rick Jaffa and Amanda Silver (Rise of the Planet of the Apes) and Shane Salerno (Savages).

The three sequels will be filmed simultaneously starting 2014, but they will be released separately. Avatar 2 will open in December 2016, followed by Avatar 3 in December 2017 and Avatar 4 in December 2018.

The first Avatar was released in 2009, and has become the highest-grossing film of  all time with global sales of $2.78 billion.