"I was always ready to live off nothing if I needed to. As long as I didn't owe anybody anything, I'd survive," he says about his lack of a back-up plan if acting didn't pan out. "I'd be willing to do anything. I'm not precious. I'd wash dishes."
Fortunately for the Brit, it hasn't come to that.
Roache is probably best known for his work on two Law & Order series from 2008 to 2012, but of course has had his fair share of "the usual disappointments" in Hollywood.
"I did a few things ... a pilot that didn't get picked up. It was one of these periods where (I thought), 'Gee, what's going to happen next?' But I had to just go for it. I had to put it out there that I really wanted to work. I went out for a lot of things and got close on a few things."
And eventually, his History Channel drama Vikings popped up.
This latest role as King Ecbert on Season 2 of the series leaves him unrecognizable.
"I am hairier," he laughs. "With the length of the hair and beard, I'm in disguise."
Hair and makeup aside, bringing history to life has been a great learning experience for the actor.
"The Vikings themselves are fascinating creatures," he says. "They're human beings of course, but their ethos are so different from ours. The fact that they live as warriors – their willingness to die for the sake of what they believe in – is quite shocking to us, and it's fascinating to see."