Movie and TV critic Mark Titus says Avatar: the Last Airbenders sequel will be called Avatar: Lost, as seen in the short film.
It will star a female lead and the first female-led film since the show’s debut in 2010.
The new film is due out in 2018, with the first episode premiering this September.
The Last Avatar, which was written by Michael Dante DiMartino and directed by John Musker, followed a group of young Avatar fans who set out to rescue the Avatar, a young man who has been taken away to the world of Aang.
The film received mixed reviews from critics.
The first film grossed $1.2 billion at the box office.
Avatar: Avatar: Two Towers, directed by Michael Bay, was a hit for Paramount Pictures, but was released only in China.