Zoe Saldana is nervous about the release of the 'Avatar' sequel.

The 43-year-old actress will reprise the role of Neytiri in the forthcoming sci-fi epic 'Avatar: The Way of Water' and admits that is "nerve-wracking" that James Cameron's long-awaited movie will finally hit cinemas at the end of this year.

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."

Zoe explained that the preparation helped her performance as "this world has to become alive in your imagination".

She said: "Obviously, there are reference pictures, and Jim (Cameron) always has screens that are alive, and he's showing you a very rough version of what the environment looks like.

"But you have been prepping yourself so much, and you believe so much in Pandora that it's just not a difficult journey for you to make."