FANS of the X-Men comic books will know that Dr. Moira MacTaggert is one of the most sympathetic characters in the X-Universe. A long-time friend—and occasionally more—of Professor X, she runs a Mutant Research Center on Muir Island, and is a leading expert on mutant genetics. She’s also Scottish and, crucially, entirely human, completely devoid of powers. She was portrayed, briefly, in X-Men: The Last Stand, by the British actress Olivia Williams.

The Moira of X-Men: First Class, however, is a different kettle of fish. She’s an American, who acts as a liaison between the CIA and Charles Xavier’s burgeoning band of mutants as they work together to try to stave off the Cuban missile crisis. This time, she’s played by the Australian actress Rose Byrne, best known for her starring role on the hit TV series Damages, and turns in movies as diverse as Sunshine, Knowing and Get Him to the Greek. We spoke to the 31-year-old about First Class’s ’60s setting, about Moira’s relationship with Charles, and about superpower envy.

How is your X-Men experience so far?

The cast is lovely. Such a great group of people. It’s been superfun. It’s actually really collaborative in a way. We go over ideas for the scenes and it’s evolved a lot as it’s been made, which is fun. I didn’t expect that. I think we’re trying to inject it with a sense of fun and a twinkle in the eye.

So the swinging ’60s vibe must have helped, then.

It really does, yeah. I think that will give it a whole different take on it. I haven’t seen that before. Personally, I love the idea of it being in the ’60s. I loved that my character is one of the first women to work for the CIA. It was a great prospect to work with James McAvoy—most of my scenes are with him, and I was a big fan of his. I thought it would be fun. It’s so exciting and so different from Bridesmaids and Damages.

Moira is not a mutant, so does she get to do a lot of stunts?

No, she’s a straight man. There’s a little bit toward the end, but she doesn’t go crazy. She gets involved in the action in a way.

Do you have mutant envy?

I kinda do! We were talking about powers the other day at dinner. We were going round the table, saying what could our power be if we were a mutant? Invisibility was a big one. Reading people’s minds was another big one, and so was flying. I was with January (Jones, who plays Emma Frost) and some friends and all of a sudden we were talking about mutant powers. It was cool. I hadn’t had a conversation like that in years!

Would you use your power for good, or for evil?

You’ve gotta be for good, right? But what’s good and what’s evil? What’s good to me could be bad for that person....

Can you talk about the relationship between Charles and Moira in this movie?

It’s fun. It starts off and Moira is very honorable and hardworking and she’s doing it for the CIA and Charles is this flirty cat who’s just after Moira’s tail. They have this initial clash and then slowly start to win each other over. He’s so much fun and we just hit it off.

Is there a romance?

Kind of. Sort of. Yes. A little bit!

Were you a comic-book fan before this?

Not particularly, no. It’s been great. That was the other thing that excited me about doing this. There was this fantastic guy that came to the set who’s an X-Men genius and he has every comic ever written. He would compile folders for us on our characters. I got here and he gave me this whole thing on Moira. That made me excited, looking and seeing that this character already existed and how she looked.

It’s not as literal as that—she’s Scottish in the comics but American in the movie. That was really fun to have that visual and that excited me to play with that character in this whole universe that exists. I went on Wikipedia and the entry about her was like War & Peace!

We’ve seen Moira onscreen before....

She was in the third one, played by Olivia Williams. But in this one, she’s more contained. I tried to make her fun and uppity and slightly annoying, but hopefully not too much! She’s like the justice of the peace, trying to keep things right.

Are you trying to incorporate elements of Olivia’s performance?

For me, not so much because that character was only in a few scenes. James (McAvoy, who plays Prof. Charles Xavier) does reference Patrick (Stewart) a little bit sometimes, but it’s basically pretty loose. Bryan Singer is overseeing the whole thing so it’s very much authentic and in that sense, it’s all the same people. In terms of characters, they’re not trying to be so anal about it.

How does Moira fit into the story?

She has an antagonistic relationship with Magneto because he doesn’t trust any humans. He’s very not into integrating at all. He thinks they should be separate. She thinks the opposite—she thinks these powers could be used to help and fight in the Cold War. She’s inventive and has these ideas and is passionate and ambitious, so there’s tension between those two. He doesn’t trust her and believe her and thinks she’s having an affair with Charles. There’s that tension there. I saw Moira as a bit of a producer of the whole thing. She’s the one representing the government and the one that has the idea and she wants it to work and she’s passionate about it and passionate about mutants. She’s the innovator, in a sense, and that humans and mutants can assist each other.

What sort of director is Matthew Vaughn?

He’s very collaborative in a sense. He’s really into hearing your ideas and answering your questions. He has a sense of fun about him and a sense of cheekiness. He’s also pretty fluid and he can change as he goes, and he can discover things on the day and on the set. He’s been great—getting to know him more and more has been good. He spent some time in Australia so we had a good bonding session! He’s been a lot of fun.