The stars of the hit film franchise "The Hunger Games" recognize the responsibility they have to stay true to the essence of the original novels.

Julianne Moore, who plays President Alma Coin in the upcoming "Hunger Games: Mockingjay" film, said her role comes with a "huge responsibility to the book".

"There are some things that have been written that the fans are adamant be there," Moore told Digital Spy. "We're taking that responsibility very seriously."

Moore, who is currently starring with Liam Neeson in the thriller "Non-Stop," felt her experience playing Sarah Palin in "Game Change" did not influence her role as "Mockingjay's" stern president.

"They don't have a whole lot to do with one another," she said.

"When you're playing a real person, all your research is really about how that person speaks and moves and is physically."

It was also recently announced that Robert Knepper, who has appeared on "Arrow," will be playing Antonius in "Mockingjay" part 1 and 2.

Antonius is not a character in the book, and many fans are not happy that the film is straying from the original story.

When MTV asked Knepper for details about his new role, he said, "I don't even know yet!"

"I know what I read for. I read, this was last summer... This is a huge movie," he said. "This is a huge two movies, and I know that what I got is not what I'll end up doing, they're so secretive about this."

He read a role by reading "sides," or short pieces of script that give a peak into the character without reading from the movie script itself. This is done to prevent leaks and spoilers, as well as because a role may have minimal dialogue, and the casting director may need to see more in an audition.

Knepper will be going to Paris in April to shoot his segment of the film.

"You're going to find out when I find out," Knepper said, referring to his role. "Well, I'll find out a little bit sooner than you, but I still haven't found out for sure!"

"The Hunger Games: Mockingjay, Part 1" hits theaters nationwide on Nov. 21.