Elle Fanning attends the screening of "Once Upon A Time In Hollywood" during the 72nd annual Cannes Film Festival.

Elle Fanning attends the screening of "Once Upon A Time In Hollywood" during the 72nd annual Cannes Film Festival in Cannes, France.

Mike Marsland/WireImage

Once Upon a Time in… Hollywood, Quentin Tarantino’s highly-anticipated, semi-controversial ninth film, had its premiere today at the Cannes Film Festival. The movie tackles the summer of 1969, aka the summer of the Manson murders, when the spirit of the sixties died (it’s arguable that that happened with the Kent State shootings in 1970, but that may be quibbling over semantics). And while the material, especially regarding the brutal murder of the pregnant actress Sharon Tate (played by Margot Robbie), is horrifying, the film looks undeniably stylish–the new trailer is all bouffants and burnished leather, yellows and Hockney blues, with Brad Pitt and Leonardo DiCaprio lit in a golden Los Angeles glow. So it’s no surprise that the movie’s red carpet premiere was full of Extremely Good fashion.

Pitt, DiCaprio, and Tarantino himself all showed up in dapper tuxedos, and models like Winnie Harlowe and DiCaprio’s (21-year-old) girlfriend Camila Morrone wore glittering gowns. Michelle Rodriguez showed out in feathers.

Brad Pitt and Leonardo DiCaprio at the "Once Upon A Time In... Hollywood" Cannes premiere.

Photo by Andreas Rentz/Getty Images

But some of the best looks directly referenced the film’s mid-century milieu, becoming instant-classic red carpet moments. Consider Elle Fanning.

Elle Fanning at the "Once Upon A Time In... Hollywood" Cannes premiere.

George Pimentel

Elle Fanning, a Cannes juror, is having a glorious festival, gracing dinners and red carpets in the most decadent, elegant Old Hollywood looks imaginable (one even made her faint, which is disturbing but glamorous). She doesn’t appear in Once Upon a Time in... Hollywood, but she had the outfit of the day in over-the-top Dior. Elle’s styling–the enormous tulle skirt, the floaty pussy-bow blouse–served as an homage to Christian Dior’s New Look, the designer’s successful attempt to revitalize overtly feminine dressing after the deprivation of World War II.

But the best part was the macramé hat! The hat. That hat better get its own Twitter account.

Stylist Samantha McMillen worked with both Elle and her sister Dakota, who stars in Once Upon a Time as Manson girl Lynette “Squeaky” Fromme, who eventually tried to assassinate President Gerald Ford (she was not successful). The actress channeled early ‘60s glamour in a very Betty Draper white silk gown with a train by Armani Privé; a Chopard necklace took the look into full Grace Kelly territory.

Dakota Fanning at the "Once Upon A Time... In Hollywood" premiere at Cannes.

George Pimentel

And then there was Margot Robbie, who is already getting rave reviews for her performance as Tate. Robbie, in Chanel (she’s the label’s newest fragrance ambassador), took the most overtly ‘60s tack–she wore black sequined trousers and a pale pink tunic top with a rose embellishment, with dramatic eye makeup that recalled Tate’s style.

Margot Robbie at the "Once Upon A Time... In Hollywood" premiere at Cannes.

Mike Marsland

This movie better be good. But if it isn't, the red carpet style certainly will be.

Related: First Reactions to 'Once Upon a time in Hollywood': "Shocking," "Brilliant"