Quentin Tarantino amazed by Margot Robbie

Margot Robbie and Leonardo DiCaprio star in Quentin Tarantino's Once Upon a Time ... in Hollywood.
Margot Robbie and Leonardo DiCaprio star in Quentin Tarantino's Once Upon a Time ... in Hollywood.

Recently at a Beverly Hills hotel the famous quartet of Margot Robbie, Leonardo DiCaprio, Brad Pitt and Quentin Tarantino were chatting away with a group of journalists.

Tarantino had a confession to make.

In their new film Once Upon a Time ... in Hollywood the two-time Oscar-winning filmmaker went to extreme lengths to physically transform modern-day Los Angeles into 1969 LA for the movie.

The work his production team did on Hollywood Boulevard and other city streets, locations and freeways without the use of digital effects was extraordinary.

But Tarantino revealed he did not put much effort into the dialogue he wanted Robbie to say.

Robbie played Hollywood starlet Sharon Tate in the film, and Tarantino said it was not until "literally just before" doing the scene he would come up with lines for the Queenslander.

"I'd think about it for a second and then I'm like, 'OK, so when you go in here and you say this, then you can say this, you say this and then you can say that," Tarantino confessed.

Robbie, DiCaprio and Pitt were smiling and laughing as they listened to their mad scientist screenwriter-director divulge his filmmaking process.

Robbie did not mind the late notice.

The 29-year-old apparently has a photographic memory and thrived.

"Margot remembers them all and commits to them as if they were written scenes that we had rehearsed for three weeks," Tarantino said.

"It was kind of amazing."

DiCaprio and Pitt had worked with Tarantino before so knew what to expect.

"Quentin has carved out his own vernacular with his contribution to cinema and it's so much fun for us," said Pitt, who starred in Tarantino's 2009 Inglorious Basterds.

"It is some of the best a dialogue you'll ever get to chew on."

Once Upon a Time ... in Hollywood centres around DiCaprio's character, Rick Dalton, a fictional actor known for a hit 1950s western television series who, in the late 1960s, is struggling to develop a movie career.

His good friend and stunt double is Cliff Booth, played by Pitt.

Dalton lives in a small Hollywood Hills home neighbouring the gated estate where Tate lived with her husband, filmmaker Roman Polanski.

The psychopath Charles Manson, played by another Australian actor, Damon Herriman, pays a visit.

"I just love the outsiders' perspective of this voyeuristic look at two kind of working class guys and culture has sort of passed them by and the industry has passed them by," DiCaprio said.

It was Robbie's role alongside DiCaprio in Martin Scorsese's The Wolf of Wall Street in 2013 that catapulted her into Hollywood's top tier of actors and led to last year's best actress Oscar nomination for I, Tonya.

Robbie said she would have been happy to do the catering for a Tarantino film if it meant being able to watch him work.

Tarantino said he was not aware of Robbie's desire to hang around on the set even when she was no longer shooting.

Robbie's agent, he said, had negotiated for the actress to go in and shoot her scenes in six weeks so she could move on to the next project.

"We said, 'Well, I guess. Yeah, sure. OK'," Tarantino said.

"It was like a normal thing for an agent to push for."

Then when Robbie discovered she was no longer needed on the set she sent a message to Tarantino.

"Then all of a sudden I get this note from Margot, 'Hey, what's going on? What's the matter? Why are you dropping me?'," Tarantino said.

Tarantino said he replied "I'm not dropping you" and Robbie told him "I want to be on set when I'm not working. I'm doing this to watch you work. Do not get rid of me early. I want to be here on the last day".

Robbie said often film sets are artificial with green screens and actors forced to use their imagination to perform a scene.

Tarantino's sets and locations looked and felt like 1969 LA.

"It was just so magical and amazing," she said.

"So often I feel like you have to use your imagination to pretend you're in the place and wonder how they're going to do it and how they will paint it in later.

"It was such a gift for an actor to be able to feel like you are really there."

Once Upon a Time ... in Hollywood opens in Australia on Thursday.

Australian Associated Press