I fell in love with Rebecca Hall in Vicky Cristina Barcelona and it took me five years to actually get to interview her. Who would have thought of all the movies I got her for, it would be the huge blockbuster Iron Man 3.

Hall stepped into the role of Maya Hansen, almost at the last minute. Hansen was an old flame of Tony Stark (Robert Downey, Jr.) with whom he partied at a science conference in Bern, Switzerland in 1999 before he was Iron Man. She comes back with her work complete and may be responsible for the new enemy Iron Man faces, Extremis.

With big movies like this we always hear about the casting, sometimes before it’s even final in this case. Did you still have to audition?

Rebecca Hall: “No, I didn’t. I didn’t. I heard about it and I heard that they were interested in me sometime back, and I wasn’t available. And then I was available, then I wasn’t available, and I wasn’t available. They moved their dates around and then actually came to me with a firm offer. I read the script and that was it, really, and said, ‘Yeah, all right,’ after having read it.”

If you hadn’t accepted it, how would they have handled you having read the script?

Rebecca Hall: “That would have probably been a massive strategic nightmare.”

There was a line I couldn’t even write down in its entirety, but the one about being a DNA encoder running a team of…

Rebecca Hall: “Privately funded think tank…”

How many tries did it take to get that all out in one go?

Rebecca Hall: [Laughs] “I don’t know. I don’t know. I think it was okay from the beginning but I spent a long time saying it whilst walking around my house for weeks on end and making sure I could rattle it off without any issues. So I was fairly well prepared when we came to shoot it. But yeah, it was a bit of a tongue twister.”

Working on a film like this were you being directed 1:1 by Shane Black like on any other movie, or was there more of a Marvel team giving input?

Rebecca Hall: “I’d imagine that there is a sort of Marvel team aspect to it as well, but I didn’t see that too much. It was mostly Shane, was my experience, but of course Marvel have a huge say in everything. That’s what makes them Marvel films.”

What was your take on Maya and did it change according to Shane’s feedback or anyone else’s?

Rebecca Hall: “My take on Maya was fairly straightforward from the beginning. I think I was quite vocal about the fact that I was hopeful that just because she was a scientist didn’t mean that they were going to want me in a lab coat and have me looking very serious. I was interested in the idea that she’s a genius and this is a world where geniuses tend to be quite eccentric, so I wanted that. I wanted her to be quite wry and humorous and maybe wear more idiosyncratic clothes than one would expect for a scientist to wear, or a botanist, whatever you want to call her.”

She doesn’t like being called a botanist.

Rebecca Hall: “Yeah, I know, she doesn’t like being called a botanist. You’re right, exactly. So that was my firm idea and everyone really wanted that too, so it was quite straightforward really.”

I noticed she wore flats to the Bern party and was wearing sneakers later. Was that part of that eccentric quality?

Rebecca Hall: “Yeah, exactly. It was all comfort. I wanted her to wear sneakers as much as possible, colorful sneakers. I thought that would be good – and clashing colors and funny colors.”

How much of the Malibu house explosion scene were you actually in?

Rebecca Hall: “A fair bit but you’re never in as much as it looks like you’re in when you’re watching it. That was all new to me when I saw it. I was really amazed by it. I had to do a fair amount of…I seemed to spend days running out of smoking buildings and rolling over bits of debris and jumping onto a crash mat, but that was it.”

Was that all on a set or was some of it on green screen?

Rebecca Hall: “There was a green screen part, but nearly all of it was a set.”

When you’re playing such a duplicitous character, does every scene have several layers you have to keep track of?

Rebecca Hall: “Yeah, for sure, but that’s what makes it fun and that’s what makes it challenging is being able to give away just enough to make her look like she’s not giving up everything that she’s about but at the same time not revealing anything. It’s quite a fun line to balance on.”

What were your thoughts on the theme that you can start out in a noble pursuit and get corrupted?

Rebecca Hall: “Well, my thoughts are it’s quite a realistic portrayal of what happens to people who have great intentions and consider themselves to be full of integrity and want to make a difference. Oftentimes it’s not straightforward and you have to make compromises, I suppose. Her journey’s quite an interesting lesson.”

Can you relate to it at all in the acting field? Is there any parallel?

Rebecca Hall: [Laughs] “Uh, uh, yeah.”

How do you relate to it?

Rebecca Hall: “What do you think the parallel is?”

I guess maybe doing something for money that you’re not really interested in or proud of.

Rebecca Hall: “Sure.”

So how have you been able to avoid those decisions?

Rebecca Hall: “Separating the experience from the outcome, not thinking about what it means for my career as much as would this be something fun to do and will it make my life better for having done it, and will I enjoy the experience and learn something?”

Did you have to keep up with Robert Downey Jr.’s improvising?

Rebecca Hall: “Yeah, yeah. To be honest with you, that was the main reason for deciding to do it was I’ve always been a huge admirer of his and wanted to know what that was like up close and if he’s really like that all the time and what it’s like to work with him, because he raises the game for people. I thought that would be quite a challenge. He’s welcoming. He wants you to spar with him. He doesn’t want you to be a passive observer, but at the same time he’s not going to reign it in or hold back or hold your hand through it. He’s just going to throw stuff at you and you’ve either got the wits to engage with it or you’re left slightly going, ‘I didn’t say anything.'”

Are scenes with Guy Pearce and Gwyneth Paltrow more traditional scripted scenes?

Rebecca Hall: “Not necessarily, actually. I think Downey sets a tone for these films, and Shane. Shane’s not precious about the writing. It felt like a very creative environment. If you wanted to do something that you thought would improve the scene or make it better, you felt like you could do it. It was very supportive in that sense so yeah, I think all the scenes were. The scenes with Gwyneth were very loose as well. It wasn’t so rigid.”

Did a lot of your lines end up being unscripted?

Rebecca Hall: “I wouldn’t say a lot but I’d say probably about a quarter. It’s one of those films that I had no idea what it was going to be like when I watched it because I sort of have my way of spouting so much nonsense, anything could have made it. [Laughs] It was quite interesting watching it and seeing what random lines did make it in and what didn’t. Not that I remember a lot of it.”

Was Maya in the comic books?

Rebecca Hall: “Yeah, she was in Extremis, Maya Hanson. She’s a very different kind of character.”

Does she look anything like you?

Rebecca Hall: “Not really. She’s got long brown hair, maybe a little bit.”

But what you said about coming up with her look, that was independent of the comics?

Rebecca Hall: “Yes, because the storyline is very different to the comic book, where Maya is. There are elements but no, if we’d gone for how she looks in the comic book, it would’ve all been jeans and tank tops.”

They probably had to change it because if it were exactly like the comic book, the fans would all know what happens.

Rebecca Hall: “Exactly, exactly, and also Marvel can’t really necessarily follow the comic books as they are anymore because there are so many narrative strands that are different now post-Avengers, post Iron Man and 2 that you have to be faithful to the movie world as opposed to the comic book world up to a point.”

I thought Lay the Favorite was adorable. Were you happy with that movie?

Rebecca Hall: “I loved that role. I think the movie was perhaps not what everyone thought it was going to be, but I love that role more than anything that I’ve done, really. She was just so much fun to play.”

I saw it at Sundance so I don’t know if they’ve changed it significantly.

Rebecca Hall: “I think they did. I never saw the final cut. I know that there was a tussle and a thing, and I don’t know what happened.”

Usually when they say that I see it again and I can’t tell what they’ve changed.

Rebecca Hall: “I hope so. I felt a bit precious about it and vulnerable about it so I ended up not watching whatever cut went out. I don’t know. It’s not really my domain anymore. Like I was saying before about separating the experience from the outcome, I don’t want it to taint [the experience]. If I’m not happy with it, I’d rather not watch it. I think Stephen [Frears] and everyone involved in it is great.”