"Diana has written these fantastic stories, so we had a lot of material we could draw upon -- that combined with the great scripts we had been given," the 34-year-old Scottish actor told UPI in a recent phone interview.
The TV drama follows the adventures of Caitriona Balfe's character Claire, a British former World War II combat nurse, who is magically transported through an ancient stone circle to 18th century Scotland.
Heughan plays Jamie, the lion-hearted Scottish warrior with whom she falls in love while trying to make her way back to modern day and her academic husband Frank, played by Tobias Menzies. Menzies also plays Frank's evil ancestor and the British army officer of whom the time-transplanted Claire runs afoul.
"We hadn't heard of the books before we were first asked to audition, but I think we both went out as soon as we found out there was a book and got copies and they've been great source material to go back to during shooting to just see where the characters are," Heughan said. "And, every time I do, I'm quite sort of surprised about how close we are to the book. I think it's certainly a conscious decision to remain true to Diana's books."
So, how would Heughan describe his on-screen alter ego?
"He's a very forward-thinking guy for that period," the actor replied. "Sometimes there are conflicts between him and the Claire character because he is trying to teach her how to survive in his time and she is trying to teach him to be more modern in his thinking, but I think that is what draws them together. They are both quite forward-thinking, but they are also resilient and adapt to situations. [Diana] has written this great character. When you first meet him, you think he's one thing and, I think, as the show progresses, you find out more and more history about him and he has to gain a lot of responsibilities, especially getting married."
Teased about how often healer Claire must patch up Jamie after battle, Heughan offered: "He puts his body in the line of honor and I think he is so used to having no responsibility but himself, so he is quite happy to throw himself in [the path of danger.] But that changes, as well."
Outlander is to premiere on Starz Saturday. The cable network is offering a free sneak preview of the initial episode online and through on-demand platforms all this week.
Heughan is a stage actor also known for his work on TV's Doctors.
2014: The Year in Music [PHOTOS]