Julianne Moore Julianne Moore

To prepare for her role as Sarah Palin in HBO's upcoming film, Game Change, Julianne Moore hired a vocal coach, read Going Rogue and watched her TV docu-series, Sarah Palin's Alaska.

"That's frankly adorable," Moore told reporters Friday at HBO's winter TV previews. "She's a very caring and a very involved parent. ... I think that was something that was very compelling and very interesting."

The film, based on the book of the same name, follows Sen. John McCain's campaign from the start of his search for a "game-changing" vice presidential candidate to his and Palin's ultimate defeat in the 2008 election. "The entire country had a collective gasp when she walked on stage. People were like, 'Oh my gosh, who is she? Where did she come from?'" Moore remembered. "It was quite historic actually."

Sarah Paulson, Peter MacNicol join HBO's Game Change

Moore found Palin relatable because they're both mothers, but also because of the pressure Palin felt during the campaign. "I chased down an ice-skating coach once because they messed up the music to my daughter's ice skating program," she said with a laugh. "Certainly when you are called upon to perform that way with that much pressure, it's very relatable."

Moore said she hired a vocal coach immediately after she was cast to capture Palin's "idiosyncratic" way of speaking, knowing that Palin's speech and movements were still fresh in people's minds. "We were all very familiar with her and with those sort of iconic moments. It was just four years ago," she said. "I'm portraying a real human being and it's my responsibility as an actor to portray them as accurate as possible ... her moments of brilliance and populism and charisma, and her lack of experience."

Ed Harris to play John McCain in Game Change

The one piece of research Moore wasn't able to do was meet with the woman herself. Palin declined to be interviewed by screenwriter Danny Strong for the project (25 people from the campaign were interviewed) and Palin also shot down a personal request from director Jay Roach. "I wrote a long letter explaining that we would just do better at getting this story right if she would just talk to us," Roach said. "I got a very quick e-mail back from her attorney saying, 'I checked; she declines.'"

Although Palin is still very much involved in the political sphere — despite her decision not to run for president in 2012 — those involved don't think the film will affect how people view her politically. "We felt that the story of Sarah Palin is truly one of the great American political stories of our time. It's so dramatic. It's so exciting. You have such a great character at the center of it," Strong said. "There's not an agenda here."

Game Change premieres on Saturday, March 10 at 9/8c on HBO.