Spike Lee’s new movie is “Da 5 Bloods,” the story of black soldiers in the Vietnam War.

In an interview with Mark Leepson of VVA Veterans, Lee said that the movie was originally written with white characters. But when he was brought in to direct, he reworked it to focus on black soldiers, and he brought in experts to advise him and showed the film to black Vietnam veterans to get their feedback.

The veterans were not shy about telling Spike Lee what didn’t look right in the movie—and what did. And Lee took heed. “Those guys helped us,” he said. “I listened to them. They were there while I was in high school. They really, really helped us. And I knew that if they liked the film, then I had done my job. No way would I make a Vietnam War film and not let those guys look at it. They were there. Brothers died in their arms.

“I made the film for them,” he said. “I made the film for those guys who were 18 years old, boys who were trained to be killers and went overseas and never were the same. And they were the ones who were lucky; they came back. That was much of the justification for this film, that we had those four screenings for those vets and they loved it.”

That said, Lee said, “this film is not just for black Vietnam vets. There’s an adventure segment to this film that can be captivating, too. It’s not made exclusively for black Vietnam vets.”