Avatar: The Way of Water: Trailer finally released for sequel to James Cameron's hit fantasy adventure

A trailer has been released for the much-anticipated sequel to Avatar, the highest-grossing film ever.

It starts with a group of Na'vi leaping in the treetops and flying over the sea riding winged creatures on their planet of Pandora.

The lush visuals that helped make the original a phenomenon are again front and centre of the new adventure, entitled Avatar: The Way of Water.

The 2009 film combined computer-generated imagery (CGI) with revolutionary motion-capture techniques using live actors and was a huge hit, taking over $2.8bn at the box office.

Zoe Saldana, Sam Worthington and Sigourney Weaver return in the new film, while Kate Winslet, Vin Diesel and Michelle Yeoh also appear.

The only line in the new trailer is by Worthington's character, Jake Sully, who says: "I know one thing. Wherever we go, this family is our fortress."

Director James Cameron, behind other hits such as Titanic and Terminator 2, is shooting four sequels - doing two at a time.

The third film in the series is understood to be almost complete and he's promised they will be the best-looking 3D films ever.

Avatar part two comes out in cinemas on 16 December.