It could be argued that director Pablo Larraín’s probing new biopic “Jackie” offers a perfect example of what happens when an irresistible force meets an immovable object. Working from a script by Noah Oppenheim (“Allegiant”) that should be studied in journalism programs as a model of investigative focus, we get “the” immovable object—First Lady Jacqueline Kennedy, the trend-setting style maven who truly gave birth to the notion of the White House as the People’s House. While she certainly was not as issue-driven as, say, Eleanor Roosevelt, Jackie Kennedy shaped our conception of the power of crafting an iconic image to represent the dreams and aspirations of a nation.

Larraín dared to challenge this idea of Jackie Kennedy by casting the irresistible Natalie Portman as the First Lady. Portman has labored, somewhat effortlessly, under the burden of being an eternally youthful ingénue. Most discerning film fans remember her on-screen debut as the orphaned Mathilda in Luc Besson’s nihilistically violent action-thriller “The Professional” (1994) who becomes the protégé of an assassin in order to exact revenge on those responsible for her family’s deaths. She followed that up a year later with Michael Mann’s “Heat,” where she played a wounded teenager struggling to gain much-needed attention in her fractured family.

But it was in “Beautiful Girls” (1996) where Natalie Portman became the subject of meta-level awareness. As the preternaturally cute, teenage next-door neighbor to a now-grown man (Timothy Hutton) at the crossroad, where love and life are forcing him to make tough defining choices, director Ted Demme presented the dilemma of our fixation on Portman herself. Was she the American beauty we had been waiting for, and, if so, were we willing to creepily pine away for her, when there was still a degree of inappropriateness to our gaze?

Obviously, we decided to overlook any internal conflicts, assuring ourselves that we were zeroing in on her undeniable talent over the superficiality of her appearance. And she tended to work with us, choosing roles that accentuated performative brilliance (“Cold Mountain” and “Closer,” which earned her an Academy Award nomination for Supporting Actress) rather than naked grabs for It-Girl status.

That doesn’t mean she shied away from the franchise world—she was a featured player in the “Star Wars” prequels (as the eventual mother of Luke Skywalker and Princess Leia) and made her way into the Marvel Cinematic Universe as Jane Foster in the “Thor” movies—but it was no surprise when she snagged an Oscar as the lead in “Black Swan.”

The win finally legitimized our untoward fascination with her, although it now sets the stage for a seemingly epic clash.

So, how can we reconcile the merging of the iconic Jackie Kennedy mystique in the person of Portman who, despite having earned our respect and admiration over the years, still feels, even after all this time, like that cute little orphan girl with the big doe eyes?

We would all be wise to consider that at the time of the filming of “Jackie,” Portman was nearly the same age (34) as Mrs. Kennedy at the time of the assassination, and once she slipped into that dark wig, settled into the shoes and gowns, and adopted the brittle and measured accent of the First Lady, there was no going back—for her or us. Portman wraps herself in the period trappings and the familiar elegance of the Jacqueline Kennedy persona. The real marvel of her work now stems from the simple idea that she makes it impossible to imagine anyone else in the role.

Larraín and Oppenheim meticulously recreate the setting and find ways to evoke the majesty of the taped White House tour and the tragedy of the hours and days immediately following the shooting, but in the end, the film belongs to Portman. The performance rises beyond mere imitation, as Portman unearths intimate secrets beneath the stylistic façade that Kennedy presented to the world.

“Jackie” shows us how Kennedy gave birth to the legend of the modern-day Camelot, but it also captures the ongoing evolution of a star, right before our eyes.