James Cameron brought a little of Pandora — and a lot of his starry cast — to London for the “Avatar: The Way of Water” world premiere on Tuesday night. The long-promised, eagerly-awaited sequel has been 13 years in the making, and now it’s finally set to debut in cinemas in just a few days, a moment the director wasn’t always sure would come.

“I had a lot of doubt when the pandemic hit,” Cameron told Variety on the blue carpet in Leicester Square. “We got shut down for six months. We didn’t know if there were going to be any movie theaters left to release the movie into. But we’ve survived all that. The theaters are full again. It’s all back. We’re all sold out for the first few weeks. So yeah, pretty happy!”

“The Way of Water” reunites Cameron with his “Titanic” star Kate Winslet, who joins the franchise as Ronal, a leader of the water-based Metkayina clan. The actress found the shorthand they had previously established to be very useful as she jumped into the world of Pandora.

“He would say, ‘Do whatever you want.’ He trusted the script that he had created,” Winslet says. “And he trusted the actors to get in there and bring it all to life. So it was just ‘Show me. Play. Try anything.’ It was just fantastic.”

“Jim is a trailblazer. He’s pushing the technology and pushing us as actors,” adds Sam Worthington, who reprises his role as Jake Sully, who along with his wife Neytiri (Zoe Saldaña) must protect his family from a familiar threat. “Jake is still a reckless warrior. Now he’s got kids, so he’s got a big responsibility because the whole journey is about family and protecting what you love.”

That “familiar threat” is once again embodied by Stephen Lang as the villainous Quaritch, this time in a genetically-engineered autonomous avatar body of his own. Speaking to Variety, Lang reflected on two very different first days on “Avatar” and “The Way of Water.”

“Day one on the first ‘Avatar,’ I was working in the armor bay. It was a very controlled scene. I was in my element. I was in the weight room. That’s where Quaritch… he’s in his shit there,” Lang said. “Then on ‘The Way of Water,’ the first scene I shot was the first scene we shot of the movie, which was Quaritch waking up in his new incarnation and being completely disoriented and lashing out. So he was really not in his element at all. But they’re both total Quaritch moments.”

The cast and crew of “Avatar: The Way of Water” at the film’s London premiere.
(L-R) Brendan Cowell, Jamie Flatters, Jack Champion, Jon Landau, Stephen Lang, Kate Winslet, James Cameron, Sigourney Weaver, Trinity Jo-Li Bliss, Zoe Saldana, Bailey Bass, Sam Worthington and Joel David Moore
Gareth Cattermole/Getty Images f

Bringing those and many other moments to such vivid life requires high level visual effects, and Weta Digital’s Eric Saindon noted his excitement in helping bring the 3D experience back to theaters.

“Everyone saw the first ‘Avatar’ in stereo, and it was brilliant. Everyone loved it. And then 3D got really boring. I stopped going to 3D movies, because it didn’t add to the film,” he explained. “This movie brings you into the world. You don’t realize you’re watching 3D. You just watch it and you think ‘I’m part of Pandora.’ Jim knows how to use stereo to add to the film, not just as a secondary thought.”

Inside the cinema, the audience was treated to excerpts of composer Simon Franglen’s score, before producer Jon Landau introduced the stars on stage.

Cameron hailed the night as being “not just about a new ‘Avatar’ film. It’s about the cinema itself. To see all of you here, looking so beautiful in your finery, to celebrate this art form that we all love so much on the big screen — the way it was meant to be seen.”

He continued: “I feel so grateful that we’re all here to do that, and that cinema is back, as vibrant and powerful as it ever was. So let’s do this, let’s have some fun, let’s put on our 3D glasses and let’s journey back to Pandora, together!

“Avatar: The Way of Water” debuts in theaters on Dec. 16.