"I try to use public transport, always. My obsession is plastic packaging. It makes me sick, all the waste. Everything about it disappoints me," says Theo James, star of the new CBS cop drama "Golden Boy." The set isn't as green as he'd like. "They do try and make an effort, but there is a lot of plastic packaging and forks and paper cups."

The native of Oxford, England relocated to New York — and adopted an American accent — to play the "Golden Boy" titular star, a young man who has rapidly risen through the NYPD ranks to become the youngest Police Commissioner in history, and tells his story, seen in flashbacks, to a writer. "What I liked about this story is the development of a single, ruthless person," says James. "You see his journey. I think he comes from a very dark place. He's from a crime family and he had a choice whether or not to do that and he chose the other direction. He's smart. There was some abuse that went on and that fuels him. He wants to disassociate himself from that part of his life."

James appeared in the movie "Underworld: Awakening" and the British series "Bedlam," but is best known for his brief appearance in season one of "Downton Abbey" as the doomed young Turk, Kemal Pamuk. "I had 20 minutes of screen time, having sex and dying. Rather salacious," he says. He hasn't seen the third season, but is a fan of the show. "I knew that it was going to be great."

His "Golden Boy" liaisons are not lethal, but are noteworthy. "The main one happens toward the end of the season and that is a significant thing for him because he's a lone wolf. He opens up to this girl and it changes everything for him and not in a good way," he says of a relationship with a journalist.

James, who'd actually considered becoming a cop post-college, took the immersion approach to playing a New York detective, working with a dialogue coach and speaking with an American accent from the moment he got in the van to ride to the set until he wrapped for the day. He found the Big Apple similar to London. "Six months in New York and I'm in love with the city and everything to do with it," he raves.

If "Golden Boy," which premieres Feb. 26, is a hit, he might find himself playing the same role for years, which is "completely unheard of" in Britain. "Normally you do six episodes and it takes three months max. I obsessed with that a bit," he admits. "I thought, 'Am I signing my life away?' But if it's successful enough to run that long I shouldn't be complaining!"

Get more celebrity updates and read more entertainment news.