Tom Blyth, who stars in the Epix origin-story series “Billy the Kid,” is British — but he knew all about the famous Wild West outlaw/gunslinger before landing the role.

“I was a big Western fan growing up. I knew his legend, I had seen his picture. I knew him as an iconic name. But I hadn’t done deep reading,” said Blyth, 27, who’s based in Brooklyn.

“Billy the Kid,” premiering Sunday (April 24) on Epix, was created by Michael Hirst (“Vikings“). It’s an adventure series set mostly in the 1870s and depicts a dramatized version of Billy’s life, starting from his humble roots as the son of Irish immigrants living in New York who decide to search for more opportunities out West. 

“When you get told you’re playing this historic character, you kind of feel a responsibility to do right by them and tell their whole truth,” said Blyth, who’s also known for HBO’s “The Gilded Age.”

“But for someone like Billy, there’s no video footage of him, no recordings, I can’t go and learn his voice. But what I can do is read as much about him as I can, and then interpret and build something from the ground up as he speaks to me from beyond the grave, so to speak.”  

In the series, Billy’s family finds that life out West isn’t the land of opportunity as it was advertised to them in New York. Billy endures years of hardships, including losing his family to consumption after grueling work for low pay and harsh living conditions. 

“So much of who we think he is is based on him being an outlaw and a killer,” said Blyth. “But in the script, he’s a fully-formed human being who plays music and is a flirt and a charismatic person. I was like, ‘I thought he was this rugged outlaw?’ But, you dig deeper into history, and all the accounts of him describe him as a multitude of things, as well as being a killer, eventually. But he started out as a young boy who was raised by a good woman with incredible values, at a time when it was hard to be morally sound, because most people were just fighting for their survival.” 

Billy (who reportedly killed at least eight people, escaped from jail several times, and was fatally shot at age 21 in 1881) loved his devout Catholic mother, Kathleen McCarty (Eileen O’Higgins). On the show, circumstances push him to turn away from a lawful life; as he encounters corrupt authorities, he sees that trying to make an honest living sends the rest of his family into misery and early graves, and he befriends the robber and gang leader Jesse Evans (Daniel Webber, “The Punisher”).

“I had two weeks of quarantine when I first got to Calgary [where the series was filmed], so I spent that time with a practice pistol on Zoom with my stunt double, practicing [drawing and twirling the gun],” Blyth said. “On set, you want to be able to not think about it and just pull it out, like it’s second nature.

“But the beauty of it is that in the show, we see Billy learning these skills in real time. We get to see him growing as a person and as an outlaw, and I got to grow with him. As I was learning to twirl the gun, Billy was learning to twirl the gun. As I was learning to ride [horses], Billy was learning to ride. It gives it this grittiness and authenticity.”

In addition to reading history books, Blyth said he also took a road trip to New Mexico and Arizona, visiting locations that were part of Billy’s life, including Silver City and Fort Sumner.

“I just tried to walk in his footsteps as best I could,” he said. “As much as I told myself it was about research, I think a bit part of that for me was actually almost like asking permission from his spirit, his legend, his myth – whatever you want to call it. Just kind of saying, ‘Okay, I’m doing this.’ It was a pilgrimage, almost — to cement that I was honoring him, and to make it tangible.”