Syfy's upcoming series 12 Monkeys faces a huge challenge: how can a series based on a popular movie distinguish itself from its original source material?

That question was answered when we spoke to series stars Aaron Stanford and Amanda Schull about how their version of 12 Monkeys matches up with Terry Gilliam's film, as well as how difficult time travel really is.

Stanford began by stating that he's a "big fan" of the 1995 Terry Gilliam film and that's why he signed on to the project, but he also pointed out a little known fact: that Terry Gilliam's film was actually based on a 1962 short film called La Jetée.

"It was basically the same plotline but it was a very different execution," he says. "It was a small bite-sized chunk and then 12 Monkeys took that and they expanded it and made it their own. And now what we've done is the same thing. You know 12 Monkeys is the inspiration and it's the source material, and we took that and we turned it into something different and much more expansive."

Schull agreed and stressed that the Syfy series stands on its own: "You don't need to be just a fan of the film or just a fan of the series," she says. "We're not constrained by time. So we have a lot of different characters that are introduced and, with guest stars and storylines, it will be interesting for people who love the movie and people who aren't familiar with the movie."

Both Stanford and Schull are filling some pretty big shoes in the series, taking on roles previously played by Hollywood heavy hitters Bruce Willis and Madeleine Stowe. But both Stanford and Schull stated a need at the beginning for separating themselves from those portrayals of their characters while also being true to those original depictions of the characters.

Stanford started with the character that Willis portrayed in the film: "For me, it was a really interesting role for Bruce Willis, what he did with it," he says. "He's generally remembered for his action roles, like John McClane. And he really brought this child-like innocence to the role in 12 Monkeys, and it was expressed in his experience. This was a man coming into an unimaginably unpleasant, difficult place where all of the pleasures, comforts, and everything were stripped away from him.

"So his experience of our world was very similar to that of a newborn. He's experiencing everything for the very first time and I really liked that choice and that idea, so I did try to bring a little bit of that to my performance as well."

Schull, though, stayed away from the source material as much as possible: "I didn't re-watch the film before we shot the pilot," she says. "I didn't want Madeleine's performance to affect my performance because we're different characters and I don't think I could ever do her performance. She's brilliant, right? So I made the choice to be different from that, how we are different characters in a lot of senses, with different careers and a different life trajectory."

But Schull admits some similarities. "Going forward in the series, I did watch the film. I think that the soft spot that Dr. Railly has for Cole is probably a very similar dynamic as in the film. That a lot of things can happen on the periphery but at the core there's a connection between the two characters."

So what's it like to film a series based on time travel, especially with so many timelines present at any given time? Both actors agreed that it's often confusing, so how did they deal with keeping their timelines, and characters, straight?

"Thankfully there's a large army of people devoted and dedicated to keeping all that information straight, but yes, it can get very confusing at times, particularly when dealing with situations and scenes where there's multiple versions of yourself running around," says Stanford. "I was definitely confused by it, but there were always plenty of people on set that you could turn to if things get to be a bit too much."

Schull agreed, but added that she also has her own way of keeping down confusion between scenes. "I am also a very meticulous note taker, so I usually have my notebook on set, even for things that they wouldn't necessarily be," she says. "I have my own notes on what my character knows, what she doesn't yet know, what has happened and what hasn't happened yet, because with time travel it can get a little bit confusing for sure. Not only for Aaron's reasons where there might be multiple versions of yourself, but also in different years, what you may or may not know and what has or hasn't happened yet."

Fortunately, it seems that the army of time travel record keepers on the 12 Monkeys set keeps everyone in line and you can see the results for yourself when the series premieres on Syfy this Friday, January 16.