Farah Nayeri, a culture writer for The New York Times, questioned Tarantino over Robbie's limited role, despite being a star in her own right and one of the leading names cast in the 145-minute film.
While Tate paired her hairstyle with a slinky spaghetti-strap dress, Robbie opted to wear a bohemian off-the-shoulder white lace Chanel frock with a tulle hem.
Robbie, meanwhile, said the lack of lines actually helped her get into character.
Adding that she thinks "the movie is good, thankfully", she admits that "the concept bothers me".
"I think the moments that I got on screen gave an opportunity to honour Sharon and the likeness". But, the film isn't exclusively centred on Tate this case, and, as we know, you don't have to have a massive amount of lines to make an impact on screen; Anthony Hopkins was only on screen for 16 minutes for all of Silence of the Lambs - it's often what you do with the screentime given that counts. I think the tragedy was the loss of innocence.
"I feel a responsibility with every character I play, whether they're fictional or real life..."
In Once Upon A Time In Hollywood, Quentin Tarantino had Rafal Zawierucha as Polanski and Margot Robbie portrays Sharon Tate, Roman's second wife who was murdered by the Manson family when she was pregnant with their child in the summer of 1969.
"I did get a lot of time to explore the character even without dialogue specifically, which is an interesting thing because I often look to the interaction with other characters to inform me on the character". According to Emmanuelle Seigner's Instagram post shared on Friday, Deadline reported that she wrote harsh words for the director.
'I am just saying that it doesn't bother them (in Hollywood) to make a film which takes Roman and his tragic story. while at the same time they have made him a pariah. The 85-year-old has remained a fugitive ever since, despite repeated attempts to have him extradited back to the US.