BlacKkKlansman author Ron Stallworth on his advice to John David Washington and his conversations with David Duke

“He just glared at me, and I glared back at him with a smirk on my face because I knew I had beaten the Grand Wizard,” Ron Stallworth tells EW of a fateful moment with former Ku Klux Klan leader David Duke. “At that moment, I owned the Klan. He didn’t say anything, he just stared at me, then he turned around and walked away over to where his followers were and started giving his speech on white supremacy, even though I had basically destroyed everything he said minutes earlier with my actions.”

Stallworth, the real-life inspiration behind Spike Lee’s newest film BlacKkKlansman and author of Black Klansman: A Memoir, still crackles with energy and passion as he recalls his time as the sole black detective in the Colorado Springs police department in 1978-79, during which time he successfully infiltrated the local chapter of the KKK. Stallworth first established contact with the hate group over the phone, but just as it was depicted in the movie, Stallworth’s first in-person meeting with Duke was tense: he was assigned to guard a local KKK meeting Duke was attending. While he was on duty at this meeting, Stallworth asked to take a photo standing next to Duke, and at the very last minute threw his hands around the white supremacist, provoking the horrified reaction as described above. “Duke didn’t say anything after I said I’d arrest him for assault of a police officer.” Though Stallworth no longer possesses that photo, he remembers how good it felt to pull one over the Grand Wizard in his own place of power.

Aside from a few changes and fictionalizations for the sake of story, Lee’s film is pretty loyal to Stallworth’s real-life tale, depicting the many phone conversations between the undercover Stallworth (John David Washington) and Ku Klux Klan leader David Duke (Topher Grace). Although Stallworth was not heavily involved in the actual filming of BlackkKlansman, he did offer advice to Washington when needed. This came in handy during the filming of said party scene, when Washington was weirded out by the experience of acting alongside dozens of actors in white KKK robes: He called Stallworth to ask how the now-retired detective had once managed to keep his cool surrounded by real Klansmen.

“It was kind of a funny conversation,” says Stallworth, who spoke with EW ahead of his appearance at the Thursday screening of the film at Brooklyn’s Alamo Drafthouse. “He said ‘Ron, I know this is a room full of actors dressed like Klansmen, but it’s intimidating as hell to be in a room with them. How did you stand up to that? Weren’t you intimidated or afraid?’ I said ‘No, I was a trained undercover cop, and we don’t get afraid, we do our job.’ I told him to just hang in there, recognize that you’re the one in charge, you’re the officer, they answer to you not the other way around, and project that. The next day they apparently filmed it, and what we see on the screen is the end result.”

That KKK meeting was not the end of Stallworth’s conversations with Duke. Decades after the conclusion of the investigation, Duke called Stallworth out of the blue last Sunday to voice his concerns about his portrayal in the film’s trailers. Their conversation lasted for an hour, and covered topics from President Donald Trump’s views on race to American history. Once more, Stallworth ended the interaction feeling he had gotten the best of the white supremacist.

“He obviously felt the need to call me because he went through the process of finding my number. He was basically concerned about his image in the movie and how he’s gonna be portrayed,” Stallworth says. “He was basing it on what he saw in a couple trailers. He told me, ‘I never said anything like that. I said you expressed thoughts like that.’ He told me he respected me, he read my book and liked it, and he said he liked and respected Spike Lee’s work.”

Stallworth says he and Duke went beyond the film. “We talked about issues about Trump. He said, ‘Trump’s not racist.’ I said, ‘Yeah he is.’ He said, ‘Trump is just promoting white culture and heritage.’ I said there’s no such thing as white culture and heritage, it’s a myth. He cited the fact he’s of Germanic and Scandinavian descent, and that’s the culture that built America. I said America was founded by rich slave-owning white men, some of whom were rapists. I cited Thomas Jefferson. He said ‘That’s not true.’ I said ‘DNA tests have proven it to be true,'” Stallworth says of he conversation with Duke, a former Republican Louisiana State Representative. “Every time I cornered him, he would change the subject and move on to something else. We talked about a whole range of stuff, that’s just a sample of it.”

Duke did not respond immediately to EW’s request for comment on the conversation.

In the closing minutes of BlackkKlansman, Lee’s tale transitions to real-life footage of the violent 2017 Unite the Right protests in Charlottesville, Virginia — showing that the KKK’s legacy is alive and well in America today. But when it comes to identifying white supremacy at work in America, Stallworth doesn’t think labels are as important as ideology.

“What I tell people is, don’t sleep on the Klan. They’ve always been around, they always will be around in some form or another,” Stallworth says. “Don’t focus on the fact that this movie is about that particular group, because whether they call themselves the Klan or Neo-Nazis or skinheads or the alt-right or Republicans, they’re all the same. They’re just interchangeable parts. We shouldn’t sleep on that fact, so recognize that and stay vigilant to it. And be prepared to confront it when the opportunity presents itself.”

BlackkKlansman is in theaters now. Following this week’s screening in Brooklyn, Stallworth will attend film screenings at Alamo Drafthouse theaters across the country. He’ll be in Raleigh, North Carolina on Friday, followed by Dallas on Aug. 22; Katy, Texas on Aug. 23; Austin on Aug. 24; and San Antonio on Aug. 25.