Kate Winslet talks 'Avatar' sequel, breaking vow not to work with James Cameron again and that 'Titanic' door debate

"He has a temper like you wouldn't believe," Kate Winslet once said Titanic director James Cameron, adding in that same interview that she would only work with the famed filmmaker "for a lot of money."

The two reunited, however, for this week's highly anticipated sequel, Avatar: The Way of Water. Winslet, co-star of Cameron's famed 1997 romance blockbuster, joined the cast of the follow-up to Cameron's famed 2009 sci-fi blockbuster Avatar as the oceanic Na'vi warrior Ronal.

"I think we're just older, wiser, different people," Winslet told Yahoo UK in a new interview (watch above). "Creatively, hopefully, I've gone away and learned a lot of things and he has, for sure, evolved enormously as a director and as a person."

Read more: Kate Winslet appears in Avatar 2 underwater set photos

She added: "He's driven and determined the way he always was but, my god, he's just such a genius. To watch him at work and to see the detail that goes into it, he's really running the show. He's the only one who ultimately knows what needs to happen in order to achieve his vision. And he's always right.

"What's lovely is that, when he isn't right, now he will say: 'Yeah, that was kind of a mistake. That was never really gonna work, but I just wanted to try it to see and yes I was wrong.' So it's really kind of reassuring to know that he is able to say 'I could've had a better idea for that thing'. Any of us are like that, so I really appreciated that about Jim. It was fantastic."

Read more: James Cameron explains importance of 3D in Avatar 2

In the film, Winslet's Ronal and husband Tonowari (Cliff Curtis), leaders of the green-hued, seafaring Na'vi clan called the Metkayina, take in Jake (Sam Worthington), Neytiri (Zoe Saldana) and their family as refugees.

Ronal is expecting during the film, which Winslet describes as being a hugely important facet of the character.

"Pregnant women are capable of doing a lot. People don't always necessarily think that. Jim knows what women are capable of, and is totally in awe of it. I love that he included that in his film because he clearly has so much admiration for the physical ability of pregnant women. It was a wonderful thing to be a part of," she said.

Read more: Kate Winslet felt objectified in past film roles

With Winslet's previous work for Cameron also being water-based, her role in the Avatar sequel raises the specter of a certain ocean scene from 1997 — and a notorious chunk of door.

"It's funny, the door seems to have had a resurgence over the last few years. I don't know why," said Winslet, says of the scene's famous ending in which Jack (Leonardo DiCaprio) sacrifices himself so that Rose could survive by floating alone on a dislodged door. Fans have long debated whether both could have made it.

Read more: James Cameron says Jack had to die in Titanic

"People seem to be doing all kinds of experiments as to whether or not they could've really fit on the door," Winslet says. "It's hilarious. It's one of those unanswerable questions. We'll have to just go back there again and see if we could really both get on that door eventually."

Working on Way of Water, Winslet's underwater survival skills became legendary. During one sequence, she held her breath underwater for seven minutes and 14 seconds, breaking a record set by Tom Cruise.

Winslet explained that she was "surprised at how well I could actually do it," but always thought it was a skill she could learn given the chance.

Read more: Explaining the CGI innovation of The Way of Water

"I knew going into it that it was something I was going to be really at ease with, and I knew there was the potential that I could maybe get quite good at it just because I was never afraid," she says. "I was able to relax myself enough to be able to hold my breath for quite long periods of time sort of from the outset. But when I did that big breath-hold, I couldn't believe it. I was very proud of myself and I was amazed that I did that."

Avatar: The Way of Water opens Friday.

Watch the trailer: