Leonardo DiCaprio Raves Over Lily Gladstone's 'Killers Of The Flower Moon' Performance

Leonardo DiCaprio couldn’t have higher praise for his newest leading lady.

The Academy Award winner teams up once again with director Martin Scorsese for “Killers of the Flower Moon,” which adapts the acclaimed non-fiction book that chronicles the horrific massacre of Osage Nation members over oil-rich tribal land in the 1920s.

Leo and co-star Lily Gladstone told Access Hollywood’s Zuri Hall about bringing such a harrowing piece of American history to the big screen and how they bonded over their common goal to make sure the movie was as authentic to the Osage experience as possible.

“Marty was so vigilant about listening to the Osage community about their perspective on how to tell this story,” Leo shared of the filmmaker, adding that he found it an “honor” to be part of the project.

“We were privileged enough to be able to be able to try to go in and be as truthful as possible about not only what happened but the essence of who these characters were,” he added. “I feel so mentally proud of this movie.”

For Lily, who already has major Oscar buzz for her performance as Osage woman Mollie Burkhart opposite Leo and co-star Robert DeNiro, she said the most important truth she wanted to convey is that the Osage people, and Native Americans overall, have continued to survive after such incredible hardship.

“Even though the reign of terror is specific to Osage it’s also part of a whole period of time where we have the assimilation era following the removal era for American Indians,” she said. “Every big step this nation has taken has been a step closer to our erasure, and yet we’re still here.”

Leo explained how impressed he was with not only Lily’s talent, but also Scorsese’s trust in her as the right actress and artist to bring this adaptation to life.

“As soon as she came on she just took this, Marty looked at her, he wanted her in a leadership position and a collaborator to really help us steer how to tell this story correctly and not only did she embody the spirit and the soul of this character but she really helped us with the narrative of what we wanted to say. It was an equal partnership,” he raved.

WATCH: Leonardo DiCaprio’s ‘Killers Of The Flower Moon’ Scores 9-minute Standing Ovation At Cannes

Lily noted that her and Leo’s camaraderie and professional connection was evident from their initial meetings prior to shooting.

“I mean, we had a couple of dinners beforehand, which I really appreciated because then I got to just get to know the Leo within the Leonardo DiCaprio of it all,” she chuckled.

Lily also confirmed that she never formally auditioned with the Hollywood icon and recalled how surprised she was to find out she’d landed the role before the pair had even read lines together.

“I was anticipating the next call I would get, if I got one, would be for that read. So when I got a call from both my agent and manager I was like, ‘Oh, this is news’ because they usually call if it’s big news together,” she told Access.

“They gave me the part and I was like, ‘Wait, no, no, we’ve got one more step!'” she laughed, adding that she “threw the phone across the room” and “screamed.”

As if that weren’t meaningful enough, Lily added that the timing carried particular significance to the story she was about to tell.

“That was Dec. 1, and nobody planned it this way but Dec. 1 is Mollie Burkhart’s birthday,” she said, prompting a “wow” from Leo.

“So right away I had the excitement but then it was like, ‘Oh, that’s a good reminder of what I’m actually here to do,'” she said.

“Killers of the Flower Moon” is in theaters now.