Advertisement

Robert De Niro Began ‘Mumbling’ the Osage Language in His Sleep While Making “Killers of the Flower Moon” (Exclusive)

Robert De Niro Began ‘Mumbling’ the Osage Language in His Sleep While Making “Killers of the Flower Moon” (Exclusive)

“He was spending every waking minute trying to get it right,” recalls De Niro's costar Lily Gladstone

Robert De Niro takes his work home with him.

In the new issue of PEOPLE, the actor opens up about his dedication to his latest film, Killers of the Flower Moon, which tells the harrowing true story of the Reign of Terror in 1920s Oklahoma.

De Niro plays William Hale, a seemingly benevolent White man who orchestrates the murders of several Indigenous Osage people to steal their oil-rich land.

As he’s done for decades in films like Raging Bull and Taxi Driver, De Niro threw himself into the role.

“When Bob commits, he starts digging in with research, questions about absolutely everything, from what the character wears to what he eats for breakfast,” director Martin Scorsese, who has worked with De Niro on 10 feature-length films, tells PEOPLE. “The search and the discoveries never stop.”

<p>Melinda Sue Gordon/Apple TV </p> Killers of the Flower Moon

Melinda Sue Gordon/Apple TV

Killers of the Flower Moon

Related: Killers of the Flower Moon True Story: All About the Real Events That Inspired the Martin Scorsese Film

De Niro took pains to learn the Osage language. “He was spending every waking minute trying to get it right,” recalls costar Lily Gladstone.

And sometimes, every sleeping minute, too. “His partner, Tiffany [Chen], has joked that he would start speaking Osage in his sleep," continues Gladstone, who plays Mollie Burkhart, one of the people targeted by Hale.

Asked about Chen overhearing him, De Niro confirms: “She heard me mumbling. I was constantly going over and over. I couldn’t stumble through that [onscreen]. You have to know it.”

The persistence paid off: De Niro’s performance has been praised by critics, and he earned his eighth acting Oscar nomination (he has one more for producing Best Picture nominee The Irishman), putting him in elite company with just 17 performers in all of Hollywood history who have eight or more acting nominations. (Think: Meryl Streep, Katharine Hepburn, Jack Nicholson, Denzel Washington.)

<p><a href="https://www.instagram.com/mschwartzphoto?igsh=MTh2djVtYWo1NTJ2Yg==" data-component="link" data-source="inlineLink" data-type="externalLink" data-ordinal="1">Michael Schwartz</a></p> Robert De Niro on the cover of PEOPLE

Michael Schwartz

Robert De Niro on the cover of PEOPLE

Fifty years ago, De Niro learned to speak Sicilian to play young Vito Corleone in The Godfather Part II — and won his first Oscar for the role. But he says learning Osage was “more difficult.”

Related: Leonardo DiCaprio and Robert De Niro Star in First Trailer for Martin Scorsese's 'Killers of the Flower Moon'

“I had some familiarity with Italian, not from any personal, just that I liked Italian. I had a feeling for it, but it was still a lot of work because it was Sicilian,” he says. “I went to Sicily for a few weeks, I was there tape recording people.”

Killers of the Flower Moon, which is nominated for 10 Academy Awards, including Best Picture, Best Director (for Scorsese), Best Actress (for Gladstone) and Best Supporting Actor (for De Niro), is now streaming on Apple TV+.

For more on Robert De Niro, pick up the new issue of PEOPLE.

For more People news, make sure to sign up for our newsletter!

Read the original article on People.