The cast of “Avatar: The Way Of Water” is taking their acting to the next level.

In preparation for the much-anticipated sequel to the 2009 smash-hit “Avatar”, the all-star cast found themselves acting underwater.

Speaking on the strange experience, Sam Worthington recalled how unexpectedly difficult it made scenes.

READ MORE: ‘Avatar: The Way Of Water’ World Premiere: Best Looks From Zoe Saldaña To Kate Winslet

“To be honest, even when he suggested the idea of it, it’s only now when people are bringing it up,” said the actor. “Does it seem crazy? Like to us doing it it that was the job. But yeah, look, those scenes are hard enough to do for actors on dry land. Let alone 30 feet deep, you know, oxygen.”

Despite the added challenge, Worthington said that in the end it was all about relying on your scene partner.

“When you’re doing it, you just rely on each other. That’s what you rely on. The tech and the water goes away,” he explained. “And it’s about a father and a son or a mother and a daughter. And that’s what you’re trying to accomplish.”

Newcomer to the series, Sigourney Weaver, said that with enough breath training, anyone could hold their breath for “six and a half” minutes.

READ MORE: Zoe Saldaña Learned To Hold Her Breath For Five Minutes For ‘Avatar: The Way of Water’

“You can do it. With our teacher. He teaches the Navy SEALs. You could absolutely do it. You can hold your breath for one minute in a pool if you slow your heart down,” said the actress. “Yeah, it would not be a problem for you. And then you build on that and you’re also, you learn how to breathe up. And also the breath holds are all static. So it’s something you do to prepare for a scene.”

Part of the training involved even breathing air with a lower amount of oxygen.

“And in our case, we were sometimes using augmented oxygen, certainly for filming. So we we have 30% oxygen in the world if we’re lucky and we had 50 to 80%,” recalled Weaver.

“Avatar: The Way of Water” will release in theatres on Dec. 16.