Kate Winslet says her "extraordinary" reaction to a death in Avatar: The Way of Water is hiding a surreal scene partner – a giant metal grate: "It was easier imagining an iceberg passing by"

Kate Winslet has revealed the surreal partner she had to act opposite during an emotional death scene in Avatar: The Way of Water.

As revealed in Disney Plus documentary Fire and Ash – Making the Avatar Films, the moment that sees Kate Winslet's Ronal react furiously to the death of her spirit sister Tulkun Ro'a was actually done with Winslet floating in a tank next to a large metal grate with an eye stuck on it.

"When [Ronal's Tulkun] dies, it's an extraordinary sequence to watch. But you would not believe what I was acting to. Even I couldn't believe it. I was thinking, 'OK, I've got to dig deep here,'" Winslet recalls. "That's very memorable to me. That's the most extreme version of imagining. It was easier imagining an iceberg passing by."

Production designer Dylan Cole was full of praise for Winslet's performance, saying, "There are times when I am in awe of what the performers can pull off. We try and give as much as we can, but she's emoting about the loss of her spirit sister to a minimally sculpted eye."

But far from taking place on a green screen or in an empty soundstage, director James Cameron went to serious measures to ensure everything was done for real – including building bespoke tanks, utilizing jetpacks, and hiring some of the world's most prominent free-divers to help make his actors feel safe underwater during filming.

"Pantomime is your enemy," Cameron explained. "You want [the actors] to have real behavior, real effort, really be tired. The more the world pushes back against the actor, the more it starts to feel real to them."

Winslet adds, "It's very physical, hard, immersive work. I can imagine how people would think it's cartoons or it's not really them. It is really those actors putting life and blood into every single one of those characters, creating that energy [and] creating that environment… Everyone is really doing it, more than you can possibly imagine."

So, grate or no grate, it's worth remembering that these actors really are in the water. Winslet herself became renowned during Way of Water for her aquatic feats, including holding her breath underwater for over seven minutes. Will that be topped in Fire and Ash?

Avatar: Fire and Ash is released in cinemas on December 19. For more, check out more movie release dates you should add to your calendar.