Tate first donned the look at the same event in 1968, just one year before she was murdered by followers of Charles Manson in 1969.
Robbie plays Tate in Quentin Tarantino‘s upcoming film "Once Upon a Time in Hollywood," which has been receiving rave reviews by critics.
The cast, including actors Brad Pitt and Leonardo DiCaprio, and the director reportedly got a six-minute standing ovation after the film premiered.
The Academy Award nominee didn't take playing Tate lightly. To prepare for the role, Robbie spoke to Tate's family and friends.
"They all said how kind, loving and good-hearted she was," she told People magazine. "I was fortunate enough to step on to set with Debra Tate’s blessing, Sharon’s sister."
When the "The Valley of the Dolls" actress was killed she was eight-and-a-half months pregnant with her first child with husband Roman Polanski. She was 26 years old.
The braided look was recreated by Robbie's hairstylist Bryce Scarlett.