She portrays murdered actress Sharon Tate in Quentin Tarantino's upcoming blockbuster, Once Upon A Time In Hollywood.
Margot Robbie has revealed a chilling detail about the role: she wore the late star's personal jewellery collection on-screen.
"It was sometimes very sad to be that closely connected with real-life Sharon," the Australian actor, 29, said in a new interview.
Robbie revealed that Tate's sister Deborah provided her some of her sister's personal possessions, which the Oscar-nominated star wears on-screen in Once Upon A Time In Hollywood.
"It kind of hit you at moments, and suddenly the tragedy of it all would kind of hit you and you would be tremendously sad, and then other times it just made me feel so happy," Robbie told the US Today show.
Robbie has been channelling Tate's style on the red carpet while promoting Once Upon A Time In Hollywood, including at Cannes where the Chanel ambassador wore her hair in loose, face-framing braids just like the hairstyle Tate sported at Cannes in 1968, the New York Post noted.
Even the white Derek Lam dress and dusty mandarin-coloured eyeshadow and lipstick that Robbie wore to a photo call in Los Angeles last week was compared to's Tate look in the movie, Twelve Plus One.
Robbie, of course, is know for her flawless red carpet style and sat front row alongside US Vogue editor-in-chief Anna Wintour at Chanel, as the luxury label showed its autumn/winter 2020 collection inside a Chanel-themed library at the Grand Palais.
The former Neighbours star was forced to defend her role in Once Upon A Time In Hollywood after a New York Times critic suggested she didn't have much dialogue as her male co-stars DiCaprio and Pitt did.
"I always look to the character and what the character is supposed to serve to the story," Robbie told the panel at Cannes in May.
"I think the moments that I got on screen gave an opportunity to honour Sharon and the likeness.
"I don't think it was intended to delve deeper … I think the tragedy was ultimately the loss of innocence, and I think to show those wonderful sides of her could be done without speaking.
"I think I got a lot of time to explore the character, even without dialogue specifically."
Tarantino delivered a less polite answer: "I reject your hypothesis."