Kate Winslet thought she died after breaking record for time spent holding breath underwater

While breaking the world record in anything is an incredible achievement, I'm sure fearing for your life in the process can be pretty scary.

Kate Winslet genuinely thought she died after breaking the record for time spent holding her breath underwater on a movie set.

The Titanic actor, who turned 49 on Saturday (5 October), was on the set of Avatar sequel The Way of Water.

The James Cameron led film dropped in 2022 and follows the continuation of the Jake Sully (Sam Worthington) story.

In the movie, Jake and Neytiri (Zoe Saldaña) now share four children together in Neteyam (Jamie Flatters), Lo’ak (Britain Dalton), Tuk (Trinity Jo-Li Bliss), as well as an adopted daughter, Kiri (Sigourney Weaver).

Kate Winslet was up against Tom Cruise’s underwater record (Michael Loccisano/Getty Images)

Set more than a decade after the first movie, they must face the threat from the 'sky people', led once again by Colonel Quaritch (Stephen Lang).

Meanwhile the oceanic Metkayina clan is led by Ronal (Kate Winslet) and Tonowari (Cliff Curtis).

On set, Winslet did 'three weeks of the training every single day' in preparation for her 'underwater' role.

In an interview on The Graham Norton Show, the actor explained how she learnt to control the way she distributed oxygen in her body.

"It's a very detailed, quite extraordinary process," she said.

Captured on camera alongside her trainer, a video shows Winslet attempting to complete the underwater task of seeing how long she can hold her breath for.

After popping her head out of the water to get her breath back, Winslet then asks: "Am I dead?"

She then says: "I don't know. It could have been 6:10. It could have been 7:10."

When the trainer revealed a record-breaking score of '7:15', the actor jumped up with joy and was absolutely delighted with the news.

She smashed Tom Cruise's record of six minutes, which he achieved while filming Mission: Impossible – Rogue Nation.

Speaking to Total Film, Winslet explained: "I have the video of me surfacing saying, 'Am I dead, have I died?' And then going, 'What was [my time]?'

Winslet in her Avatar form (20th Century Studios)

"Straight away I wanted to know my time. And I couldn’t believe it...The next thing I say is, 'We need to radio set.' I wanted Jim to know right away.

"Well, I didn't have to hold my breath for over seven minutes. It's just that the opportunity to set a record presented itself.

"I wanted to break my own record, which was already six minutes and 14 seconds. And I was like, 'Come on!' So I smashed my own record by a minute."

The actor worked with ‘elite military divers so that she could hold her breath, after a big gulp of supplemental oxygen, for more than six minutes’.

"I had some concerns… but that’s what the training was for. And I really wanted to do it. I didn’t want anyone to think, ‘Oh, she’s old, she can’t do this,'" she said.

"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."