Critics have especially been raving about Natalie Portman's performance in the title role. The Oscar-winning actress admits that playing Jackie was "right up there" with her most challenging parts. "It felt like the most dangerous role," she says. "Everyone knows her or has an idea of her. We tried to get to some things that people could get past and believe I was Jackie."

Natalie Portman as Jackie Kennedy in a new Biopic

Not having to look exactly like her lifted some of the pressure. As Larrain says, "It's not about how they look. When somebody is so well-known as Natalie and is playing somebody as well-known as Jackie - when does the audience believe it?"

Portman says that she and Larrain did a lot of research to work out both the public and the private Jackie Kennedy. "We noticed when looking at the existing film and audio tape of Jackie, her voice and presence were very different when it was a public interview," she says. "She got a lot more coy and shy. There were a lot of small details. But she was a mannequin for a lot of people."

Materials they had available included a series of interviews a year later, in 1964, with historian Arthur Schlesinger Jr. "You can hear drinks and ice clinking in the background," Portman says. "And she had a much different tone and quality of voice."

Playing all of these elements was a challenge the actress welcomed. "There are so many things she's dealing with at once," Portman says. "The loss of someone always leads to a questioning of faith, so the spiritual part was incredible. And it was incredible to work with John Hurt [who plays Jackie's priest]."

Portman thinks that what makes Jackie such a fascinating woman is the way she took on with so many feelings and experiences at the same time. "And that's why Pablo's approach is so exciting to work on," she says. "Because it comes at her from all different aspects. She's a young woman, she's a symbol for all these people. She's a mother, she's a wife, she's a betrayed wife! She's a person who's trying to figure out her way in the world."