Chiwetel Ejiofor explains the danger of going too deep 'down the rabbit hole' with an intense role

Chiwetel Ejiofor is quickly becoming one of the most reliable actors in the movie business with a string of impressive roles, from his Oscar-nominated performance in 2013's "12 Years A Slave," to, earlier this year, playing the NASA mission director who has to get Matt Damon home in "The Martian."

In theaters this weekend, we'll see Ejiofor opposite Julia Roberts and Nicole Kidman in the thriller "Secret in Their Eyes." A remake of the 2009 Argentine movie that won an Oscar for Best Foreign Film in 2010, it stars Ejiofor as Ray, a former FBI investigator who returns to the Bureau after tracking down the man who killed the daughter of his partner (Roberts) 13 years earlier. Ejiofor and Roberts give intense performances playing two people who are obsessed with the past and go to extreme lengths to find "justice."

Business Insider chatted with Ejiofor while he took a break from shooting the next Marvel movie, "Doctor Strange," to talk about his role in "Secret in Their Eyes" and the challenge of staying away from the "rabbit hole" while acting in a movie like this.

BI: You're in the midst of playing Baron Mordo, the villain in the upcoming "Doctor Strange," right?

Ejiofor: We have begun, yeah. 

BI: Pictures of you in costume have hit the internet.

Ejiofor: Yeah, cool. 

Ejiofor: Yeah. I think it's all right. [Laughs.]

BI: Well, "Secret In Their Eyes" is a very different project. What drew you to it?

Ejiofor: I had some initial conversations with [director] Billy Ray and I was just kind of fascinated by it. There's a lot of different things happening in the story and I just felt like the two time periods that it takes place in, 2001 and the present day, and seeing what happens to this guy in the time that we don't see him, having this obsessive quality, this intensity to his life, that was something that I was really engaged in. I was very excited when I spoke to Billy Ray about it. And an amazing cast, Julia and Nicole. 

BI: Were either of them attached when you were talking to Billy Ray?

Ejiofor: I don't think so. I think that all happened after that. Which was amazing. 

BI: Did you watch the original movie?

Ejiofor: I didn't when we were shooting or before, but I have since. I wanted to approach it cleanly, but I always felt there was room to do another version of it. Do a more American version of it. I think the original is great, bit it's a different kind of film. Definitely culturally.

BI: The way you play the Ray character, I saw a lot of Denzel Washington in it. You've worked with him in two films, "Inside Man" and "American Gangster." Did you think of him when doing this role?

Ejiofor: Interesting. I wasn't thinking of him actually. [Laughs.] I love Denzel. I loved working with him. 

BI: There are parts when you're controlled and then you explode with emotion and rage, which he tends to do in some roles.

Ejiofor: I suppose in some of the stuff he's done, there's an obsessional quality, and Ray definitely has that. His mind is always ticking, but it's cool that you thought that. 

BI: The subject matter is so dark. Did you have to think back to difficult moments in your life to play this role?

Ejiofor: No, not really. In a way you don't want to do personal math on stuff like this. You sort of engage in it, but at some distance, otherwise it renders it impossible to play. And I would feel that's the same for Julia with her role. You're trying to get as engaged with the emotions of it and the sense of it and the narrative of it. And the truth of it. Part of the skill of that is not necessarily having to fall down the rabbit hole yourself. 

BI: That being said, you and Julia look ragged in the movie. Your character literally says to her, "You look like you're 100 years old." Are these roles fun to play even though the subject matter is so brutal?

Ejiofor: It was pretty serious by the time we got to the scenes at the end of the movie. There was some room to be slightly lighter earlier in the movie. But things take a turn. By the end these characters are so obsessed and beaten by the circumstance that being in that mindset, it was complex and engaging. In a way it's what you want to do as an actor. So in that sense it's enjoyable. But not in the sense of funny, ha-ha. 

BI: Were there things you used through costume, wardrobe, or makeup to put you in the mindset you needed?

Ejiofor: For me, I liked that he changes his watch. You can't really catch it in the movie, but I really enjoyed that. When he goes away and starts working for the private sector, he picks it up along the way. When he worked for the FBI in the earlier part of the movie, he has a very basic watch. And as we were changing over from different time spans the watch was always something that clicked me into the difference in Ray. 

BI: You've been very busy since "12 Years a Slave" came out. This is your third film released this year. Is that daunting or do you like the constant work?

Ejiofor: I like it either way. [Laughs.] But what has been enjoyable are the projects I've been working on I've loved. Film, and over the summer I did a play in London. So trying to find that balance of film and theater has been engaging and important to me and I want to continue that. But maybe have a little more time off. 

BI: We saw you last in "The Martian," and after that movie was released, it was criticized by the Media Action Network for Asian Americans because your role, which was an Asian in the book, wasn't cast with an Asian. Did you catch wind of that, and do you have any thoughts on it?

Ejiofor: I did hear about it. I feel the film is a great example and a very successful example, I think, of diversity in cinema. And I think that really works. I suppose one isn't going to please absolutely everyone, but I think in general the principal of having both racially and in terms of gender, a lot of diversity in the film which goes on to be that successful and has very strong themes about community, was something that I was personally very gratified with.

BI: In your view, has the diversity issue improved in Hollywood?

Ejiofor: I don't know. It's too early to tell. I feel these things will probably be judged generationally. When we look back at this time in cinema, we'll be able to understand a bit more whether diversity was addressed in any way or if things improved during the '90s and into the 2000s, so it's hard to say. But as I said about "The Martian," I think it was great to have so much diversity in that film and that film being so successful, it is a prototype for how films can do that more. 

"Secret in Their Eyes" opens in theaters on Friday. Watch the trailer below.