Kate Winslet has said she learned to free-dive for the “crazy, crazy stuff” shot underwater in Avatar 2.

The actor opened up about the “incredible” filming process on James Cameron’s upcoming sequel, in which she plays “a water person”.

• Read more: ‘Avatar 2’: Everything we know about the upcoming sci-fi epic

The film’s producer, Jon Landau, posted a picture of Winslet on set filming one of the underwater scenes on Instagram. He referenced a recent interview Winslet did with The Hollywood Reporter in which she detailed the filming process.

“I had to learn how to free-dive to play that role in Avatar, and that was just incredible,” the actor had said. “My longest breath hold was seven minutes and 14 seconds, like crazy, crazy stuff.”

Kate Winslet then paused before revealing more, merely adding: “Oh no, actually, I can’t. Yeah, I play a water person. I am a water person.”

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Wanted to share this photo of Kate Winslet after reading her interview in The Hollywood Reporter: “I had to learn how to free-dive to play that role in Avatar, and that was just incredible. My longest breath hold was seven minutes and 14 seconds, like crazy, crazy stuff.” She stops herself, afraid that she’s given away too much on the top-secret project. “Oh no, actually, I can’t. Yeah, I play a water person. I am a water person,” is all she will offer, instead shifting to praise of Cameron."

A post shared by Jon Landau (@jonplandau) on Oct 26, 2020 at 9:44am PDT

Sigourney Weaver, also returning to the franchise in Avatar 2, recalled her own underwater prep which included training with “elite military divers so that [she] could hold her breath, after a big gulp of supplemental oxygen, for more than six minutes.”

The New York Times explained that the star “had weights around her waist and professional divers who sped her back to the surface for air at brief, regular intervals.”

Weaver said of the preparations: “My hope is that what I receive from the universe is even more outrageous than anything I can think of. I don’t really say to myself, ‘Well, you can’t do this.’ Or, ‘You can’t do that.’ Let me at it! And we’ll see.”

Avatar 2 is set to reach cinemas on December 16, 2022.