LOS ANGELES - In Vox Lux, Natalie Portman plays a girl who survives a school shooting, sings a song about it and becomes a huge pop star.

But as the movie attempts to dissect modern celebrity and violence, it left many moviegoers scratching their heads and critics rolling their eyes. And with a 60 per cent score on the website Rotten Tomatoes, it is one of Oscar winner Portman's worst-reviewed films in years, although her performance received praise in some quarters.

At a screening in Hollywood last December (2018), the actress and the film's writer-director, Brady Corbet, addressed the polarised reactions to their movie, which opens in Singapore on Feb 28.

Corbet, 30, says he set out to "make a movie that was about the early part of the 21st century". And one of the defining characteristics of this century is "the spectacle of evil", explains Portman, 37.

"In this century, the pageantry of evil is that violence has become theatre, violence has become about making a show - making the news and getting on TV. It's all merging in this awful way," she says.

"When I read (the script) it was like, wow, that's something I hadn't really thought about - the collision between pop culture and political life and violence."

A story about a pop star captures the dark side of fame and pop culture in a way that an actor's story could not, she believes.

"I think pop stars, unlike actors, are presenting a version of themselves, so there's more at stake in terms of their fame, because we really see their personal relationships and ups and downs," says the star, who won the Best Actress Oscar for the psychological drama Black Swan (2010).

"We see their art as a representation of their inner life, whereas for actors, we always see them as separate from their roles."

Corbet says it is no coincidence the story starts in 1999, the year of the Columbine school shooting in Colorado as well as the height of singer Britney Spears' fame.

"I'm from Colorado and I lived there when Columbine happened," says the film-maker, who is also an actor from movies such as Funny Games (2007).

"It cast a shadow over the last 20 years in this country," he says, noting the many school shootings that have followed. "I think it is one of the defining moments of our era."

Asked about how the film has divided audiences, Corbet concedes "it is a very unusual film".

"I think there are a lot of things you are not allowed to do (in films) - you are not allowed to have dramatic tonal shifts from melodrama to dark comedy and tragedy.

"But I believe in order for the film to be emblematic of the defining events of the 21st century, it had to be all of those things - equal parts absurdist and very serious."

The film opens with a shooting and concludes with a pop concert.

While acknowledging it is a "difficult pitch", he adds: "But I think the juxtaposition of the two exists in the culture and news cycle already. And with the convergence of pop culture and policy, I felt it was important to make a movie this way."

Corbet calls it an ambitious experiment and is glad that people have shown up to watch it.

"Even if people really don't like the film, I'm really thankful they spent two hours with it because it is very unusual. So I hope the whole thing opens a viewer's mind, or a part of it does. That's the best you can do."

Portman sees similarities between Vox Lux and her Oscar-winning film Black Swan, in that "both have an interest in performance and what it means to be someone who has a performative self versus a private self, and what that means".

She was also drawn to the larger-than-life character she plays, Celeste, and the "incredible dialogue that Brady wrote" for her.

"It's so extravagant, the stuff she says. It's like nonsense to real insight and back to this garbage - she's just all over the joint," the actress says. "And goes from being all pretence to a moment of being genuine.

"It was really fun to get to play with it."

Vox Lux opens Feb 28.