Speaking to Elizabeth Olsen this time of year traditionally means you’re previewing Sundance. In recent years, beginning with Martha Marcy May Marlene in 2011, she’s been one of the indie festival’s biggest darlings. This year, unfortunately, she doesn’t have a film in the Sundance lineup — but on Feb. 21, she stars in In Secret, a period romantic thriller based on Émile Zola’s novel, Thérese Raquin. Olsen plays an unhappy wife trapped in a passionless marriage to her cousin (Tom Felton, in full-on creepy Alan Cumming mode). When sparks instead fly with her husband’s dashing artist friend (Oscar Isaac), they’re tempted to knock off the man keeping them apart, never mind the withering glares of her mother-in-law (Jessica Lange).

In Secret looks promising, but Olsen is also poised to go from the art-house to the multiplex in a huge way. The 25-year-old was an essential part of Spike Lee’s Oldboy remake earlier this fall, and next year, she stars in the wait-this-trailer-almost-looks-promising Godzilla. And while that monster movie opens in May, she’ll likely be rubbing elbows with Marvel superheroes like Iron Man and Captain America as the character Scarlet Witch, one of the two new members of Joss Whedon’s Avengers.

Rest assured, Olsen isn’t turning her back on the indie world. In fact, she’ll be at Sundance in January to support her boyfriend, Boyd Holbrook, who has two promising movies screening.

In addition to the exclusive new poster for In Secret, Olsen checked in with EW to discuss the movie and what promises to be a most exciting 2014.

ENTERTAINMENT WEEKLY: In Secret is based on a play that was based on the Émile Zola novel, Thérese Raquin. How were you introduced to it?

ELIZABETH OLSEN: It was actually odd: Mickey Liddell, who’s the producer, sent me the script when I was in school and I was taking a class called Realism and Naturalism in Theater. I read the script, took the class, and our first assignment is to read the book and the play and talk about the differences between the two, and how it began this movement in theater. Which is kind of crazy, because it kind of felt like all the stars were aligned. And then I kind of really loved it from an academic point of view. The teacher would describe it as an inherently flawed story because of how quickly it moves. But I don’t know. It takes you through such a fast journey and the characters are flawed themselves, which sometimes makes people not willing to respond. It was a fun challenge.

From an acting point of view, Thérese is a pretty great character. She’s woman of a certain time, but she’s also still relateable today.

She’s pretty repressed and she’s not really given an opportunity to make any decisions for herself. The moment she see an opportunity to listen to her own desires and wants and needs, she takes it, and just one thing leads to another. It was really interesting, trying to figure out a balance of how secretive she is and how wild she is by keeping a lid on it. It’s an interesting character to try and navigate in that way.

I’m a strong believer in the magic of precision casting, and I feel like this film is really blessed with you, Tom and Oscar, and Jessica. What was it like working with the guys?

Tom’s a sweetheart. It’s so funny, because people think he plays all these mean characters, and he’s literally like the nicest person you’ll ever meet. And Oscar is just a phenomenal actor. He has a such a quiet understanding of how things are going to come across through a camera lens. And Jessica Lange, just to get to work with her, it’s such a cool memory to have.

I imagine she’d be intimidating to work with in normal circumstances, but now I can’t separate her from her American Horror Story characters.

No, she’s super intimidating — but not in an unwelcoming way. You just look at her, and there’s something about her that’s so old school. She creates this energy of knowledge and wisdom.

Thinking of some of the other characters you’ve played, in Martha Marcy May Marlene and maybe Kill Your Darlings, they’ve also been trapped — or at the very least are in unfulfilling relationships. Is that anything worth noting, or are they just well-written characters that have that in common?

I don’t know, I think it’s always fun to play people who have secrets, I guess. All I’ve been trying to do is just change things up for me, like genre-wise, tone-wise, and just trying to figure out what I enjoy, I guess. What I can learn from each experience. I don’t know, just choose jobs that hopefully won’t pigeonhole me to a certain anything.

It doesn’t look like being pigeonholed is going to be a problem, beginning with Oldboy and now with Godzilla and the Avengers sequel up next. But I’m curious: What’s the courtship like for one of these giant movies, in contrast to what you’re used to for your smaller more-indie films?

It’s funny, I’ve never had to do camera tests. I’ve never done those before, and I was surprised that both Godzilla and Avengers didn’t do it. Both directors, Joss Whedon and Gareth Edwards alike, they just kind of know what they want and they both create things and have an energy and a way they communicate their plans. They can convince any person they want to do a role to do it. They just have such amazing visions. They’re people you want to work with. They are fun, smart guys, and you know it’s going to be a good time. You trust that they’re going to do something good.

Wow, that’s really refreshing to hear. This gives me the confidence that even though they’re making these giant films, it’s in the hands of an auteur, in a way, who’s making the final casting decisions, and not 47 people from the studio.

Yeah, I’m surprised it’s not. [Laughs] In Godzilla, Gareth literally was so confused because he was given this big-budget movie of one of his favorite monster legends that he gets to play around with. And then he gets to pick a cast and they let him pick whoever he wanted — and every person he asked to do it said yes!

I noticed that in the trailer: You, Cranston, Strathairn. I was wondering, ‘Is this a John Sayles movie or what?’

The whole time, Gareth was waiting for someone to come around the corner and tell him he had cancer. Like, what’s the catch? [Laughs] He was great and so focused. It was shocking to see someone know how to manage all of that that he was given without any precursor.

Yeah, I’m so excited. We worked with each other a little bit but mainly we were just living in Canada at the same time [during filming Godzilla]. And I got close with his family, and they’re just very welcoming warm people, so I’m excited to be on their side of the world, working in London with Avengers because I feel like I have a little bit of family there already.

That franchise has Scarlett Johansson as Black Widow, but it’s pretty hard-core dude territory. Are you bracing yourself for that introduction?

No, I think that’s so fun. Oldboy was all that too. There were like three women: me, a dresser, and a makeup lady. And the rest was just like a bunch of guys, and as long as you join in on the mean jokes — because all the guys just bust each others’ balls all the time — you’re good to go.

To be fair, Joss has a pretty great reputation for building and showcasing a female action hero.

He totally does, doesn’t he? So I feel like I’ll be in good hands. Basically, he has a vision that’s his own that’s inspired by the comics and ultimately we get too create it together. That’s what was exciting for me.