Julianne Moore listened to Sarah Palin speeches for two months “non-stop” in preparation for playing the US Republican politician in TV film Game Change.

The Hollywood actress, 63, won an Emmy for her role in the 2012 political drama which follows the former Alaska governor becoming Senator John McCain’s running mate in the 2008 American presidential campaign.

Moore said she did not get to meet Palin ahead of filming so she had to be inventive when trying to get into the politician’s mindset.

Graham Norton Show – London
Julianne Moore, Paapa Essiedu, Jamie Oliver and Ricky Gervais during the filming for the Graham Norton Show (Matt Crossick/PA)

Appearing on The Graham Norton Show, Moore said: “It was excruciating because she was so well known and present in popular culture, I was terrified I’d get it wrong.

“I took all the music off my iPhone and only put on speeches by Sarah Palin.

“I’d put it on in the car and listen to her non-stop for two entire months. I was so afraid to hear anything else.”

Directed by Jay Roach and written by Danny Strong, the film was based on the 2010 book of the same name which documented the campaign for the election, which was won by Democrat Barack Obama with the man now in the White House, Joe Biden, becoming vice president.

Following the Republicans’ failed campaign, some critics argued Palin was a major component in the defeat due to her far-right leaning views and lack of political experience.

76th Cannes Film Festival
Natalie Portman, Charles Melton and Julianne Moore attending the photocall for May December at Cannes Film Festival (Doug Peters/PA)

In her latest film, May December, Oscar-winning actress Moore plays a woman who became known after her tabloid romance with her husband, played by Riverdale star Charles Melton, gripped the nation as he was aged 13 when it began.

They star opposite Natalie Portman who plays an actress who is doing research ahead of playing Moore’s character in an upcoming film.

Discussing the project, Moore said: “We really worked as a team. Basically, she’s playing an actress who’s observing me, who’s an actress playing a character who has to learn things for her to imitate as the actress in the movie. It was so much fun.”

The Graham Norton Show also saw actor Paapa Essiedu talk about Melissa McCarthy’s improvisation in their latest project together and celebrity chef Jamie Oliver discussed renewing his vows with his wife.

Comedian Ricky Gervais also reflected on his new stand-up show and Mercury Prize nominated singer Olivia Dean performed live in the studio.

The Graham Norton Show will air on BBC One on Friday December 8 at 10.40pm.