Christian Bale, Robert De Niro on reuniting for ‘Amsterdam’ in film highlighting the Harlem Hellfighters

Christian Bale and Robert De Niro’s new movie shines a spotlight on little-known American history — including the unsung heroes of a New York regiment who served during World War I.

The Oscar-winning actors star in “Amsterdam” as military veterans with ties to the 369th New York Regiment, inspired by the real-life Harlem Hellfighters infantry of Black and Puerto Rican soldiers deployed in France.

Written and directed by David O. Russell, the film presents a murder mystery that unravels into a larger conspiracy from the era.

“They’re incredible stories, and what I love about David’s films is that he takes people who ordinarily would be supporting roles in other films and he makes them the leads, and he does scenes that ordinarily you wouldn’t see on camera,” Bale told the Daily News.

“You’d assume what happened off-camera, and that’s what he’s more interested in,” the actor said. “People have the most extraordinary stories, whether they are famous or not, and so many unsung heroes, and this particular period of history really fascinated David and myself. We are jaws-on-the-floor about an awful lot of it.”

Coming to theaters Friday, “Amsterdam” stars Bale as a Park Ave. doctor who returns to Manhattan after serving as an officer of the 369th New York Regiment, and John David Washington as his best friend and a former soldier who became a lawyer after the war.

The two become prime suspects in a murder and work to prove their innocence with the help of a nurse with connections to New York’s elite played by Margot Robbie, and with De Niro’s Gen. Gil Dillenbeck, a decorated former commander of the 369th regiment.

The film marks the latest collaboration between Bale and Russell, who made “The Fighter” and “American Hustle” together, and between Russell and De Niro, whose movies include “Silver Linings Playbook” and “Joy.”

“He has that kind of energy that I’d not seen,” De Niro told The News. “Other directors have other great qualities, but this is David’s, and he makes the film more immediate, more spontaneous, more energetic, more chaotic in a good sense. Being part of that, you know you’re in something that’s going to be around and will be noted for being a special film.”

“Amsterdam” also served as a reunion for the Manhattan-born De Niro and the English-born Bale, who did a scene together for “American Hustle.”

“We’d not had a chance to really work together,” said De Niro, who won Oscars for “The Godfather Part II” and “Raging Bull.”

“‘American Hustle’ was so brief, but he was great, Christian. He’s a wonderful, great actor, inspiring actor, and it was an honor for me to work with him.”

Bale, who produced “Amsterdam,” began discussing the film with Russell years ago at a diner and watched it evolve into a large-scale project with a cast also featuring Taylor Swift, Rami Malek, Anya Taylor-Joy, Mike Myers, Zoe Saldana, Chris Rock and Michael Shannon.

“I say it was a five-year journey. (Russell) says it was six. ... It was the most involved I’ve ever been, being there right at the inception of an idea that David had, a couple of vague ideas about characters, some amazement for history that he had recently learned and he wanted to share with me,” said Bale, who won a best supporting actor Oscar for “The Fighter.”

“It was so wonderful to get the likes of (De Niro) and all of the other incredible actors who came and joined us after just a meeting in the afternoon at a greasy spoon diner between David and myself.”