The four Avatar films being produced now have official names - Avatar: The Way of Water, Avatar: The Seed Bearer, Avatar: The Tulkun Rider and Avatar: The Quest for Eywa.
For the last few years, the four planned follow-ups have simply been referred to as Avatar 2, Avatar 3, Avatar 4 and Avatar 5.
Avatar, released in 2009 and directed by James Cameron, remains the highest grossing film of all time at the worldwide box office with takings of $2.8 billion.
The 3D extravaganza starring Sam Worthington and Zoe Saldana is set on Pandora, a distant planet inhabited by a race of aliens with blue skin.
In an interview with Vanity Fair, Cameron revealed that Kate Winslet, with whom he worked on Titanic, was joining the Avatar series playing "a character who's part of the Sea People, the reef people."
The four Avatar sequels are due to be released in December 2020, December 2021, December 2024, and December 2025.