In the first part of "Avatar" actress Sigourney Weaver (72) played the character of Dr. Played Grace Augustine, who - Spoiler alert! - died in the same movie. Nevertheless, Weaver will also appear in the sequel "Avatar 2: The Way of Water".

This time she plays a teenager, specifically the teenage adopted daughter of Jake (Sam Worthington, 46) and Neytiri (Zoe Saldana, 44), who goes by the name Kiri. "I can't really talk about it, but I would say it was the biggest step I've ever taken in acting, in every way imaginable," Weaver told Interview Magazine. And further: "I think if Jim Cameron didn't know me that well he wouldn't have cast me in something so silly."

The role of the young adopted daughter apparently challenged the 72-year-old: "I had to work in a completely different way to play this character, a very physical way." The star director made sure that she didn't give up anyway: "I knew that he would present me with really unique challenges, and he won't be afraid to say what he wants."

In preparation for the sequel, Weaver also had to do a lot of exercise: "I was older than a lot of other people and we had to do a lot of parkour. We had to do burpees. We had to do freediving." With a trainer, she would have learned to hold her breath for long periods of time - a practice she would have continued at home with her husband. "And one day we held our breath for six and a half minutes," Weavers said. "That's the training. You learn that if you don't catch your breath you won't die [...] It's some psychological, very, very interesting stuff."