The film's costume designer, Madeline Fontaine, was tasked with recreating some of Jackie's most iconic looks — like this two-piece red wool dress.
According to the film's production notes, Fontaine even tracked down some of the companies that made fabrics for the First Lady back in the 1960s.
Source: Fox Searchlight
Here's the how the real Jackie looked in the ensemble.
Even when the designers didn't replicate a famous outfit, they still stayed true to Jackie's overarching sense of style. Here's Portman in a regal satin gown...
...and here's one of Jackie's actual dresses, worn to an inaugural ball in 1961.
next slide will load in 15 secondsSkip AdSkip AdIn the film, Portman stuns in a flowing red dress.
It's similar to this chiffon frock Jackie wore for a White House dinner in 1961.
This structured black dress is classic Jackie.
It looks just like one that she wore in 1961.
And this black lace number oozes Jackie's trademark elegance.
next slide will load in 15 secondsSkip AdSkip AdIt's no surprise that her real-life wedding dress had almost exactly the same neckline.
Fontaine took great care when replicating the film's most important costume: The pink suit and pillbox hat Jackie wore the day her husband was assassinated.
The design team created five different version of the suit just to make sure the shade of pink was exactly right.
Source: Fox Searchlight
The outfit became an iconic symbol of a dark day in American history.
"It was truly impressive to see Natalie in the suit the first time on set,” Fontaine said in the film's production notes. “She took on the aura of Jackie.”
Jackie was still wearing the suit when Vice President Lyndon B. Johnson took the oath of office and was sworn in as the next President.
next slide will load in 15 secondsSkip AdSkip AdThe film also stays true to the outfit Jackie wore to her husband's funeral.
Here's a photograph of Jackie and her children, Caroline and John Jr., on the day of the service.
Want to see more of Portman's looks in "Jackie"?