CIA's Nick Gehlfuss Previews the Show's Big Secret and His Chemistry With Co-Star Tom Ellis

Nick Gehlfuss has been playing the character who breaks the rules for a while. Anyone who ever watched him as Will Halstead on Chicago Med got pretty used to seeing Will be a little bit reckless and hot-headed. On CIA, CBS's new spin-off of theFBIfranchise, Gehlfuss plays the total opposite, a character who might just be a little too by the book. And of course, since someone has to play the foil, we also have Tom Ellis as his reluctant partner.

While Bill Goodman (Gehlfuss) is described as a "by-the-book, seasoned, and smart FBI agent who believes in the rule of law," Colin Glass (Ellis) is described as a "fast-talking, rule-breaking, loose cannon CIA case officer." It's the kind of partnership procedurals thrive on, and one Gehlfuss seems very excited to jump into. Chicago Med, this is not.

Still, for Gehlfuss, there's something comforting about still being in the Dick Wolf family, even if this is another network. He knows how it works. He understands the crossovers and the expectations. Now, it's just about getting to play in this new sandbox and with a new set of tools.

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The show's first episode, titled "Directed Energy," will feature FBI's Jeremy Sisto as Assistant Special Agent in Charge Jubal Valentine. In the hour, "when a top-secret weapon is stolen in broad daylight from a U.S. defense contractor, CIA agent Colin Glass is paired with FBI agent Bill Goodman to investigate. Their new partnership gets off to a rocky start, but they soon realize their opposing viewpoints may be their greatest asset."

Sounds intriguing? Nick Gehlfuss discussed with us the differences between his characters of Bill Goodman and Will Halstead, building that chemistry with Tom Ellis that serves as the centerpiece of the show, and how the FBI characters might come into play in this new spin-off.

Bill and Will might sound similar, but Bill Goodman is no Will Halstead. In fact, Will was the one breaking the rules more often than not. How's the other side?

Nick Gehlfuss: [Laughs] Yes, Will was much more like Colin, Bill's counterpart in this fusion cell, or joint task force we're creating for CIA. Bill is much more by the book. Obviously, clean-shaven, with a bit of a haircut and a comb over. But, you know, when I left Chicago Med, I was looking for a different character to play in a different playground. And this is exactly it.

I mean, funnily enough, I'm going from a Will to a Bill. You know, the name William actually means "to protect." And so, they are very much in alignment with that, in their varying ways. But you know, Bill's got a law degree; he graduated with the highest honors. And then he went off to serve two tours in Afghanistan. He's completely committed to the country. And he's very patriotic. Yeah, overachiever, probably. But he's dedicated to keeping his country safe. And of course, enforcing the law.

That feels like the setup for the character conflict between Bill and Colin.

Gehlfuss: That is the exact opposite of what he's needed mostly to do with the CIA task force, is the thing. I mean, he will do that at times, but he needs to understand that the CIA does not operate in the black and white; they're often in the gray. And I think deep down, Bill Goodman is fascinated by the gray areas of life, but is certainly not used to them.

And they can oftentimes be uncomfortable. And so, this pairing between Colin and Bill is really brilliant. It's a wonderful yin and yang of just two different methods of achieving the same objective.

Procedurals often have a way of peeling back the layers of a character so you find out who they really are and what makes them tick, little by little. How did you start building your character, and how much knowledge of what's coming up do you have?

Gehlfuss: I tell the writers that I don't like to know anything that my character wouldn't know in advance. So, they obviously have to lay out the entire season and figure that all out, because they are the puzzle makers of this entire puzzle that we're putting together.

But, specifically with this show, I did my prep work of going and learning to use a gun for the first time and building this backstory of how long this guy's been in the FBI. And I am attached at the hip with the FBI tech advisor. His name is Mike Matera, and he's fantastic. There are CIA resources as well, but funnily enough, I'm coming into this world that I'm not as familiar with. So, I don't want to be too familiar with it until I learn what I need to learn through the show.

But with the long-running procedural shows, like Wolf Entertainment usually operates under, we have the ability to continue evolving this character. And right now, I'm loving that he's in this world that's uncomfortable, and learning to build trust with his new partner. And even the office in which he works now — which is basically a magic door into a secret world, like Fort Knox, in a way — most people don't even know, yes, the CIA has a presence in New York, but no one knows where it is. And most people are not allowed in.

And Bill Goodman is going in and out and having to traverse black and white, and gray, and his position at the FBI while operating with the CIA. And then, what the audience will come to realize, certainly at the end of the first episode, is another reason he's working with this fusion cell. And it's quite a career-making opportunity for Bill Goodman. And I think any good two-person story, a relationship story, they both need something from the other. That will become very clear, and I'm excited to see where we go with all that.

As you said, this is a two-person story. But it's one rooted in friendship, instead of romance. Or one rooted in the possibility of something, because they're not really friends at the beginning. Whatever they end up being, they have to build. How do you do that with your character and with Tom (Ellis) to make it work and to make the CIA/FBI partnership work?

Gehlfuss: I love that it's not a romantic relationship. We don't see that too often. And I think that, well… the FBI and CIA don't have the best opinions of one another. And they only started working together, and maybe we'll help that with the show a little, but it only started happening after 9/11.

And so, this actually happens in the real world. But what we're doing differently here is having them be partners out in the field together, going out and about. They often share intel and work on cases and operations in an office setting together. But we're taking it a step further with the television show by having them go out and literally traveling to different areas to work cases or ops. Cases are what Bill calls them, and ops are what Colin would say.

In fact, Colin says that there are no more cases, there's only ops. And that's what the CIA does, because they work in the shadows. And they don't often make headlines because the CIA prevents… usually it's their sole goal, which the FBI does as well, to prevent anything bad from happening. But they gather intel mostly, and it's all this spycraft of how they go about doing all of that. And it really makes this show brand new in a sense, kind of a whole new procedural that we haven't seen before, outside of the typical police procedurals, medical procedurals… Wolf Entertainment started trying brand new things, like firefighting. And then moving on to FBI, and now CIA.

And I think no one can do it better than them. I'm just so excited to start sharing this with the audience.

And we get crossovers too! You know crossovers well. We get one in the first episode.

Gehlfuss: Yes, we're mixing with the FBI, and the existing world and the people who are already established there, which makes sense. It happens in real life, like I was just saying, and I think that's what Wolf Entertainment has capitalized on with what they've done.

I mean, crossovers. One Chicago. For the fans, that was their favorite part. And I get it because it's true to life. When they did the three-show crossovers, where it's one story for all three episodes, it's just never been done on television before. And you see it starting to happen elsewhere in television now, because it's a world that we want to get involved in. You see all these different types of characters, and even when they're not interacting storywise, for three hours in a row, filming them, and then airing back-to-back, makes it feel like it's still the same universe.

And I mean, kudos to them. It's fantastic. They know exactly what people want. And, I'm so glad to be here. I'm a proud member of the Wolf Pack.

We know that at the center of the show, there's the dynamic between Bill and Colin. But other than that dynamic, what was the most fulfilling for you? Which has been the biggest surprise?

Gehlfuss: Well, you know, the office. All the office antics with Necar Zadegan and Natalee Linez, who play Nikki and Gina. I love playing those scenes where Will is literally the odd man out. It's like three on one with them. And so, all of those interactions are fun to play, whether they're teaching Bill something he doesn't know, or Bill is holding court, which we know he can, given his law degree. And whenever he needs to update them on something, there are moments of that as well. But I do love this relationship that's forming with them.

There's also this ongoing relationship with Jeremy Sisto, who plays Jubal Valentine on FBI. And I can't say too much about that. But there's a reason he and I are interacting and why Bill has some interactions with some other FBI cast members over the season. There's another reason Bill is working at the CIA office that Colin is not aware of, or anyone at the CIA office.

It's a wonderful story arc, and I'm very excited to see where it goes.

Keeping secrets from the CIA guy!

Gehlfuss: Yes, indeed. He can't think he's in charge of everything. Although, having said that, Bill's a very honest man. And so, it does require him to do some things totally out of his comfort zone, and potentially puts some relationships at risk.

Interesting TV is what I'm hearing.

Gehlfuss: Well, you come to Wolf Entertainment, what else do you expect?

CIA premieres on CBS on Monday, February 23, at 10 p.m. ET, following a new episode of FBI.