After 13 years in development, the long-awaited Avatar: The Way of Water sequel has finally arrived. As former collaborators with James Cameron on two of the most successful films of all time (Titanic and the original Avatar), Kate Winslet and Sigourney Weaver spoke of the high standards Cameron sets for his cast.

Winslet also expressed gratitude to the filmmaker for the incredible roles he created for women and for allowing the cast to improvise. Ahead of the press conference for the premiere in London, she told The Hollywood Reporter that she was excited about joining the cast.

“His capacity to create incredible female roles is just amazing. These leaders, these women, they have power, they have physical strength, they have emotional gravitas. It’s very exciting to be invited in to play a character who is so in line with how I see the world and how I hope to be as a parent and as a woman.”

The actress plays Ronal, a fearless matriarch who thrives in the underwater world of Avatar: The Way of Water. However, in the story, she is reluctant to welcome Neytiri (Zoe Saldaña) and Jake Sully (Sam Worthington), together with their four children, to their oceanic community.

Related: Avatar: The Way of Water Director James Cameron Responds to 'Cultural Impact' Criticisms

Avatar: The Way of Water Required the Actors to Hold Their Breath for Extensive Periods

Avatar: The Way of Water
20th Century Studios

As part of this role, Kate Winslet had to undergo extensive underwater diving training. The possibility of holding her breath for seven minutes and 14 seconds never occurred to her. However, she knew she would be able to do it quite well.

"Everything about it was completely phenomenal. I mean, you don’t imagine when you are a person in your 40s who’s had three children that you’re going to learn something new and actually be good at it,”

In addition to Winslet, Sigourney Weaver returns to the Na'vi with a whole new character from 2009's Avatar. In collaboration with Cameron, they built the character of 14-year-old Kiri, the oldest child of Jake and Neytiri. In the same Hollywood Reporter interview, Weaver also discussed her views on Cameron's approach:

“I think [Cameron] has so many women in his life that he really admires and respects and Kiri … I feel like she’s an adventurous spirit in all of us,”

She also explained that being a member of Avatar's crew is unlike any other job. She believes the team needs to be at 200 percent to meet the bar. Sam Worthington mentioned that the plot was extended nicely by having Saldaña and Worthington become the nurturing parents to Neteyam (Jamie Flatters), Lo’ak (Britain Dalton), Kiri (Weaver), and Tuk (Trinity Jo-Li Bliss).

“[It isn’t] a carbon copy of the first one. There’s something very elemental and base about this family, and I think we kind of leaned into that. It is about protecting your family, protecting the family that you choose.”

Zoe Saldaña added that she found a way to deal with the enormous pressure the first Avatar put on them:

“I would be lying if I told you that it doesn’t pop up. But as soon as that thought comes in, it has to leave because at the end of the day, what made Avatar so special is the fact that it was all heart and it was a labor of love … And at the core of it, it was a love story.”

Avatar: The Way of Water premieres on Dec. 16, and you can watch the latest trailer below: