Martin Scorsese blocked Leonardo DiCaprio from improvising on their new film.

The filmmaker has reunited with the actor and his regular collaborator Robert De Niro for the epic 'Killers of the Flower Moon', and he has reflected on the actors' respective approaches, with the former's "endless" discussions and improvisation on set.

Speaking to the Wall Street Journal, Martin laughed: "Then Bob didn’t want to talk.

"Every now and then, Bob and I would look at each other and roll our eyes a little bit.

"And we’d tell him, ‘You don’t need that dialogue.’ ”

The film marks the sixth time 'Gangs of New York' star Leonardo has worked with Martin, while the filmmaker has now teamed up with Robert on 10 films.

But this is the first time the actors have appeared together in a full-length movie by the director.

The 'Taxi Driver' maker teamed up with Eric Roth to pen the script for the film based on David Grann's 2017 book of the same name, which focused on the FBI investigation into the murders of Osage Native Americans in Oklahoma throughout the 1920s.

Leonardo was originally lined up to play head investigator Tom White.

Martin ended up completely overhauling the script after two years, and changing the story's focus to the character of Ernest Burkhart and his marriage to an Osage woman named Mollie.

After changing the script, Martin switched Leonardo's role, giving him the part of Ernest, while Jesse Plemons took on the role of Tom White, who became a supporting character.

And it was Leonardo who felt the story should be told from the Osage community's perspective instead of the bureau agents investigating.

Speaking to The Irish Times, Martin said: “Leo came to me and asked, ‘Where is the heart of this story?’

"I had had meetings and dinners with the Osage, and I thought, 'Well, there’s the story'.

"The real story, we felt, was not necessarily coming from the outside, with the bureau, but rather from the inside, from Oklahoma.”