As Franklin Saint in FX's new series Snowfall, British actor Damson Idris plays a (mostly) level-headed teenager. He's the kind of kid who goes to a nice school and respects the rules of his strict mom...until he discovers the cocaine business and starts selling crack. Idris is nothing short of captivating as the man undergoing moral decline in South Central Los Angeles — a neighborhood often depicted in pop culture as dangerous, since it experienced staggering levels of gang violence and murder in the mid '80s.

Having grown up in the area, Snowfall co-creator John Singleton naturally took great pains to make sure details in Snowfall were right, including a lead actor who could get the mannerisms, accents and body language of an early '80s South Central teenager just right.

Snowfall Avoids the "Conspiracy Theories" of the Los Angeles Crack Epidemic

Damson Idris, SnowfallDamson Idris, Snowfall

That's why when it came time to audition Idris for the part — who was born in 1991, thousands of miles away in London — Singleton made him prove he was up for the part by what else? Taking him on a field trip into the tough neighborhood.

"At first, I was like, 'Oh no - another British actor,'" Singleton told TVGuide.com, alluding to recent blowback directed at black British actors playing Americans. But after Idris nailed a script read, Singleton upped the ante with a real-time audition in the South L.A. streets — specifically Crenshaw and Vernon, where in the '80s, serial killers, broad day drug buys and the sound of gunshots were normal. "I took him out on the streets and had him hang out with some folks, and nobody knew he was a Brit."

These days, the area — rebranded as South L.A. in the early 2000s — is much safer, though its reputation as a place that doesn't exactly roll out the welcome wagon for outsiders lingers justifiably. None of it phased Idris though. "He knew how to change his physicality and talk a certain way," Singleton said. "I figured if he could do it in real life, he could do it on the screen and I was like, 'Wow. You got the part man.'"

It'll be a while in the series before we see Franklin descend, but when he does, Idris' disciplined approach to the metamorphosis is alluring. "[Franklin] has a certain moral compass at the beginning, and that starts to get whittled away periodically through what he sees and what he has to do," Singleton reveals. "He's not going to be the baby-faced kid we see in the pilot by the end of the season."

Snowfall premieres Wednesday, July 5 at 10/9c on FX.