Though it's hailed Favorite Cable Sci-Fi/Fantasy TV Show in 2015 People's Choice Award partly because of their portrayal, 'Outlander' main stars Caitriona Balfe and Sam Heughan shared that there some difficulties in internalizing their characters Claire Randall and Jamie Fraser. 

Unlike other TV adaptation, Outlander is not a modern day drama that actors don comfy fashionable outfits. Its heavy drama fantasy series based on Diana Gabaldon's ongoing novel series and revolve in a nurse mystically transformed to 17th century.  In his talk during Television Critics Association (TCA) press tour, show's writer-producer Ronald D. Moore shared that they try to be religious with Gabaldon's creation.        

 "We don't make changes unless we have to," Moore said. "We start with the book's order of events in the writers' room. We then carve it up in discreet hours [and decide] what the arc is, where the characters are going, the theme. You sorta make changes along the way in order to accomplish those goals."

For 35-year-old Irish actress, it's not about steamy scenes or demanding costumes, but the imaginary world she breathes every time she's into Claire Randall.

"Sometimes I'm a little intimidated because I'm like, it's this whole world she's [Gabaldon] created and sometimes I feel like we're at the beginning of this," Balfe shared with ET Online.  

"It's been so nice that she's been supportive and it's been so nice to have her there as a source to go to."

On the other note, Heughan commented that their old-fashioned characters are dynamic that somehow they also following their footsteps.    

"You think you know these characters and by the time you get to book eight, they're completely different or they've traveled a long way, and it feels like we're at the start of that journey," the 34-year-old TV actor, who will set to star in independent film 'When the Starlight Ends,' said.  

Outlander's author Gabaldon is currently working on the ninth book of her best-selling novel.  Knowing she's the creator of this epic drama, she must be very meticulous with Sam and Caitriona. However in her interview with Vulture, Diana  was apparently satisfied with the two lead stars and described Sam as "chameleonic actor."

"He looks totally different in every single role. But they sent me two audition scenes and a chemistry test, so I could see him in his own persona," Gabaldon shared on Sam's audition that she thought he delivered better acting that she was expecting.

"The second scene was where Jamie was explaining to Claire, very logically, why he was intending to beat her. And he just played it perfectly. He was in total control of himself, and it was such a nuanced performance - the annoyance, the impatience, the love, the humor."