With just days to go before the long-awaited release of director James Cameron’s sci-fi magnum opus, Avatar, actress Sigourney Weaver, who plays a botanist who is an ally of the alien Na’vi tribe, talks about reuniting with her Aliens director.

EW: James Cameron told me he initially didn’t want to cast you in Avatar because he was concerned people would think of Ripley in Aliens.

SIGOURNEY WEAVER: He never told me that. [laughs] I got a call from Jim in about September of 2006 and he said, “I’ve been working on this for quite a while and I’d really love for you to read it.” I said, “I’d love to read it. Are you kidding?” It was a hard script to read because it’s so detailed — everything you see onscreen is actually in the script. I thought, “This is glorious but I don’t see how you could ever actually do this.” It’s like something from your dreams. This movie is a Jim Cameron cornucopia: He created the cameras, he created the world, he created the creatures, he created the costumes, he created the Na’vi language. If you talk about playing God, he’s done it — except it took him 14 years instead of 7 days.

There’s so much CGI in this movie, you spent almost the entire shoot acting in an empty room and having to imagine it was an alien world. What was that like?

There were no sets, no costumes — you were just there in the world you were putting together. We were just playing: “This is a log.” “This is a giant leaf.” “You can drink from this plant.” “This is a giant six-legged creature.” It was a lot of fun.

What was it like seeing your character’s avatar onscreen for the first time?

It was amazing. He made Grace look so much more like me than I realized he would. I was like, “Oh! That looks like me!”

You mean, if you were an 11-foot-tall blue alien.

[laughs] Exactly.

How has Cameron changed since you worked together on Aliens 25 years ago?

He’s a different man. When we worked on Aliens we were in England and the crew was like, “Who’s this young upstart? Where’s Ridley Scott?” He kept setting up screenings of The Terminator for them, and they wouldn’t show up. Over the course of the shoot, they learned who they were dealing with. Jim’s actually a nice guy. He’s demanding — he’s going to make you bring your 200 percent game — but he’s never mean and he’s harder on himself than anyone else. All these years later, he’s more settled, he’s happily married, he does this because he loves it, and he can get what he wants and create what he wants.

There’s been so much build-up to the release of Avatar. What are you expecting?

We’re going to be on a publicity tour, going from country to country. It’s going to be fun to go to Moscow. I think Jim knows some Russian cosmonauts, so maybe we can go out drinking with cosmonauts.