PASADENA -- Theo James was the beneficiary of the decision by Ryan Phillippe to pull out of the new CBS crime drama "Golden Boy." The British actor, who turned heads in a brief stint on the first season of "Downton Abbey," took over the role of Walter Clark, an ambitious cop who becomes the youngest police commissioner in New York history.

Before he became TV's latest top cop, the 28-year-old James appeared in "Underworld: Awakening," "The Inbetweeners Movie" and "You Will Meet a Tall Dark Stranger." The fact James isn't as seasoned a performer might have been a problem for the series had the producers not found Chi McBride, the veteran actor who will play Clark's partner.

James immediately felt an acting chemistry with McBride.

"I think it was something that developed kind of naturally from when we started the pilot, and there was a kind of synergy between us," James says. "There's a little bit of art imitating life. I'm fairly new. I'm a young English punk coming over, and Chi has been doing it for a long time. He's a veteran.

"So there was a lot that we could learn from each other, and we had a good natural chemistry. I really love the father and the son, the Obi-Wan and the Luke Skywalker, kind of thing. He's tempering my central morality between whether I choose the darker nature that I can lean towards or I use the law for the purpose of good."

A little bit of that chemistry is apparent during the interview.

"When you develop genuine affection for someone, at least with me, it comes through on the screen if you let it. If you just be and you don't act, then these things will come through on the screen," McBride says.

One of the reasons the chemistry is so important is that "Golden Boy" isn't a typical cop show. It starts with Clark already at the peak of his rise to power, with the journey told through flashbacks. Those scenes include some action, but the series is more about the people who have to face those big moments.

The first episode will establish a lot of groundwork for events to happen, including the deaths of some of the characters.

James understands characters dying off in a series. That's how he ended his "Downton Abbey" days when his character had a heart attack. In a few weeks, "Golden Boy" could become the role he's best known for. For now, it's the BBC series that always gets him attention. He didn't realize "Downton Abbey" was such a big hit until after he had left it.

"When I did the show, I kind of felt like it was going to be a big deal. It felt like it was a quality production, but in terms of, I mean, I'm on screen for about 20 minutes, and I still get people going, 'Mr. Pamuk.' It was very useful, and hopefully it kind of ended up having repercussions later in the series. But in terms of my later development, no, I didn't really see it coming," James says.

SHOW INFO: “Golden Boy,” 10 p.m. Tuesday (Feb. 26), KGPE (Channel 47.1)