The former Disney Channel actress, who has recently starred in the critically acclaimed Younger, is playing Tate in The Haunting of Sharon Tate, who was brutally stabbed to death in August 1969.
Tate, 26 at the time of her death, was married to director Roman Polanski and was eight-and-a-half months pregnant with their first child — a boy — when she was stabbed in their home by members of Charles Manson’s cult.
Jay Sebring, Abigail Folger, Wojciech Frykowski and Steven Parent were also stabbed at the home of the actress, whose blood was used to write on the walls.
Duff, 30, shared a photo of herself on Instagram dressed as the actress, complete with flowy blonde hair, long eyelashes and smokey eyes.
“Had the incredible opportunity of playing Sharon Tate the past two weeks in an independent movie. She was an amazing woman and it was a true honor,” Duff wrote in the caption.
Tate’s sister, Debra Tate, told PEOPLE last year, “Sharon was my mother’s world. And she was my sun and my moon and what I modeled myself after as a person.”
Manson died in November at the age of 83. He was serving nine life sentences in California’s Corcoran State Prison at the time of his death.
“I said a prayer for his soul,” Debra said of the moment after she received a call from a prison official informing her of Manson’s death.
Quentin Tarantino is also working on an untitled Manson-related film that will touch on the murders.
This article originally appeared on PEOPLE