Kate Winslet says working with 'Titanic' director James Cameron on his new 'Avatar' sequel was a "totally different" experience as they have both changed so much.

The actress starred in James' 1997 epic about the doomed ship and she has reunited with the moviemaker to appear in his long-awaited 'Avatar' sequel 'Avatar: The Way Of Water' - and she admits their working relationship has changed quite a lot over the years.

She told Empire: "Jim and I are both totally different people now to who we were 26 years ago. He is calmer, and I am definitely more hyperactive now."

In the new film, Kate plays ocean-swelling Na’vi warrior called Ronal and Kate said of the character: "She is deeply loyal and a fearless leader,. She is strong. A warrior. Even in the face of grave danger, and with an unborn baby on board, she still joins her people and fights for what she holds most dear. Her family and their home.”

The actress had to film a number of underwater scenes and revealed she learnt to hold her breath for more than seven minutes. She added: "Seven minutes and 14 seconds, baby! (It was) the most amazing thing for me as a middle-aged woman was to learn something not just new, but superhuman."

The film is due for release in December, and the original movie's star Zoe Saldana has admitted she feels nervous about the sequel.

Zoe told Entertainment Weekly: "It's exciting; nerve-wracking. Humbling as well, you know – the wait is finally over. And we get to share something that we love so much with so many people that we know love it, too." The 'Guardians of the Galaxy' star underwent a dramatic transformation to become one of the blue Na'vi and explained the sacrifices she had to make to get into character. Zoe explained: "Gamora is a much more traditional approach where you wake up at 3 o'clock in the morning and you go through the whole prosthetic process. And then kind of once you see yourself and you feel Gamora on you, obviously, you transform, you know?" She continued: "And when it comes to Neytiri, it's more of a practice. It's months of training, not just rehearsing with your director, but training with movement coaches, and travelling to the jungle and getting to feel like what it's like to make your own food with all the elements that are around you. "And once you use all of that, you do bring it into what we call the volume, which is the set, when you shoot under performance-capture."