It's hard to look at the cast of Syfy's "Being Human" and imagine anyone other than Sam Witwer, Sam Huntington and Meaghan Rath in the primary roles of roommates dealing with supernatural problems.

That is, unless you are imagining the cast of the British version of "Being Human," which starred Aidan Turner, Russell Tovey and Lenora Crichlow. In fact, there was one producer on the show that had a hard time imagining anyone other than Tovey being the show's werewolf ... at first.

"We showed up at a mix and match, and we just kind of knew that it had to be each other," Witwer, who plays the vampire Aidan in the American series, told Rabid Doll during San Diego Comic-Con last July. A mix and match is where various actors audition with other actors, a way for casting producers to find chemistry between different people.

When Huntington came up to audition, however, the actor -- best known before as Jimmy Olsen in "Superman Returns" -- impressed everyone, but there was still a single holdout on finalizing his casting.

"They all wanted Sammy, well, all except one guy," Witwer said, adding that this unnamed person is "wonderful to the show now" who helped get "Being Human" going. "He had a conceptual problem where he kept seeing Russell Tovey in his head, and Sammy is very different."

The goal for the American version was to capture the spirit that has found legion of fans for the British version, while still creating something unique.

"I think we are all pretty different," Huntington said. "Now that I have seen the [British] show, these characters are going through similar things during the day, but they are very, very different people."

To see the complete red carpet interview with Witwer and Huntington, check out the video clip by clicking here.

"Being Human" returns for its second season Monday at 9 p.m. ET on Syfy.