During a recent round-table interview with reporters in New York, Portman was asked about the film's horrific scene in which her character, first lady Jackie Kennedy, holds her dying husband after he was shot in the head, while they were riding in a car through Dallas in 1963.
"We think about what's given to us; you don't always think about the missing pieces," Portman explained, recalling how director Pablo Larrain told her: "'We've all seen the assassination Zapruder tapes, of course, but... it was a seven-minute drive afterwards to the hospital. What were those seven minutes like?' And it's unbelievable. I mean, you really think: 'That's the drama. What is that?' Holding your husband's exploded head on your lap for seven minutes, trying to get to the hospital and, so, we filmed that. It's harrowing because it's also, it's not recorded. We have no record of what happened. ... You're just like: 'OK, that was awful. The worst possible thing that could ever happen.'"
Despite trying to capture the emotional truth of Jackie's role in this historic incident with very little factual documentation, Portman said filming the scene also posed significant, physical challenges.
"It was very, very hard to do and it was like the coldest day that we shot it," revealed the actress, who is now pregnant with her second child. "We were on this highway that they had closed down so we could go in this open car and the poor actor who was playing Clint, the security [guard], he famously was perched on the back [of the vehicle] the entire time, so he was harnessed in a split, basically, for hours. The guy was a very brave actor, speeding down the highway in a split. So, it was physically difficult and it was also emotionally unimaginable."
She went on to say she was stunned to learn that Jackie -- who can be seen climbing on the back of the car in the real-life footage of the assassination -- was actually trying to retrieve part of the president's brain.
"I always thought she was trying to escape, which I was like, 'Oh, that makes sense if someone shoots the person next to you.' And it wasn't. It was that she saw a piece of his brain and she was trying to get it because she thought they could put it back in. ... You can't even imagine that your animal instinct in that moment of terror would be like, 'Oh, I have to get that to put back in his head.' It's unbelievable."
That said, did Portman ever find herself shaken after a day of filming such dark material?
"Those scenes were really, really a lot," she confessed.
Pressed to divulge whether she might want to pursue something lighter after this experience, she laughed and declared, "I would love to do a comedy."
Indicating her baby bump, she added: "I don't know. I mean, guess I'm not working for a while."