'Avatar 2' gets world premiere in London

One of the most delayed sequels in blockbuster history will finally hit the big screen on Tuesday as "Avatar 2: The Way of Water" gets its world premiere in London.

The 13-year wait for a follow-up to "Avatar", the biggest-grossing film of all time, cannot come too soon for struggling cinemas around the world.

The public will get to see James Cameron's three-hour opus next week, with the director hoping it will justify his dream of establishing a franchise on a par with "Star Wars" and the "Marvel" juggernaut.

Having been re-released around the world in recent months, the first "Avatar" is now just shy of $3 billion in worldwide revenue.

But Cameron's initial hopes of having a sequel out by 2014 saw repeated delays as his technical ambitions grew.

"Avatar 2" continues the mix of sci-fi and eco-politics -- returning to the planet Pandora where the Navi struggle to fend off rapacious humans -- as well as the groundbreaking use of 3D and cutting edge cinematic wizardry that made the original such a box office hit.

Stars Sam Worthington, Zoe Saldana and Sigourney Weaver return, alongside new additions including Kate Winslet, a quarter-century after her world-beating collaboration with Cameron for "Titanic".

It remains a huge bet for Cameron and for Disney, who have ploughed hundreds of millions of dollars not only into this film, but a third instalment that has already been shot.

That is not the end: Cameron has planned the series through to a fifth entry, with new films due every two years until 2028.