The best actors find ways to feel equally at home in the sprawling Marvel Universe and as one of the main figures in the sordid Tonya Harding story.

So it is that Sebastian Stan briefly steps away from his defining part as the Winter Soldier/Bucky Barnes and into “I, Tonya,” the Craig Gillespie-directed biopic that relishes in the strange, muddled truths of the figure skater’s life in the spotlight.

The actor plays Jeff Gillooly, former husband of Harding (Margot Robbie), who became infamous when he was convicted as one of the key figures behind the 1994 attack on Nancy Kerrigan. amNewYork spoke with the 35-year-old Stan about the movie, which opens in theaters on Friday.

Fundamentally, the main characters in this movie are unreliable narrators. We don’t know what the truths are. How does that affect you as an actor?

They were real people, and usually when you approach a script, you’re having to start from the ground up in the sense that you’re building a character, you’re imagining how it may be or whatever. But here they are existing, and you have to mold yourself to an existing thing already. Not only that, but then you have to at some point in your research abandon all your judgments and preconceived ideas of what you may have heard or what’s already been said about them and find your own separate thing into that.

It’s certainly challenging.

It’s what was appealing and got my curiosity level going, in the sense that it was scary. Anytime something is scary, I always think it’s a good sign of wanting to go and try it.

How did your sense of this very well-known story change over the course of making this movie?

What I would say changed for me in the process of 3 1⁄2 to four months, which is what it really took from the beginning to end of starting the quest for the research and shooting the movie is that, I felt like the humanity, particularly of Tonya Harding, was somewhere lost in the tremendous amount of noise that became the many, many different stories about her, what happened and him.

What does the real Jeff think of this?

I don’t know if he’s seen the film. I haven’t had any contact with him. I met with him before the movie, I met him before we started shooting, but I think maybe [screenwriter] Steven [Rogers] got an email from him saying he really liked the trailer.

You have to go to some dark places here. How much does it help to be doing that opposite someone as great as Margot Robbie?

Couldn’t have done it without her. Impossible. It’s just impossible. The good thing was we had this screen test, for me, really early on and she was there. We had, I don’t know, like an hour, hour-and-a-half that we spent together with Craig. It was the three of us circling each other and trying to find out and go, “OK, how are we going to do this, how do you like to work.” Margot was very generous and at the same time very open to wanting to find the truth of the moment and at the same time, honoring the tone that they were going for, which is that we’re always going to be dancing somewhere between funny and really serious.

How does making a movie in the Marvel Universe challenge you at this point in your career?

It’s certainly helped me in the sense that it’s made me more confident, it’s allowed me to have more confidence in terms of speaking my voice. Actually, those movies are far more collaborative than people I think sometimes think. I mean, we all get along. That’s really the big secret there.