At some point next week, John David Washington will know whether  his new movie, BlacKkKlansman, made more money than The Equalizer, a recent box office champ.

If that happens, some trash-talking might be in order.

Father-son stuff.

Washington's dad is Equalizer star Denzel Washington. I asked him whether a phone call might be appropriate, just to good-naturedly point out whose movie is trending in the right direction.

"No! I'd be crazy to turn that into a competition.  He's the G.O.A.T." the younger Washington said, referring to sports jargon used to designate someone as the Greatest of All Time. "But I might call my mom. She might get a kick out of it."

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BlacKkKlansman, in theaters Friday, Aug. 10, is surely in a position to make waves at the box office. It's the provocative true story of a black police detective who infiltrated the Ku Klux Klan in 1970s, and it arrives with a high profile after its splashy debut at the Cannes Film Festival, where it was heralded as a return to form for director Spike Lee.

Lee, of course, directed Denzel Washington in several films, including Malcolm X, which had a small role for John David, who by that time had already developed an interest in acting. He'd seen his father on stage in productions of Shakespeare and was mesmerized by Glory, the movie that netted his father his first Oscar win.

>> READ MORE: 'BlacKkKlansman': Spike Lee brings an amazing true story to the big screen

"I knew every character and line in that movie," said John David. But he also saw the demands created by fame and celebrity, and that soured him a bit on the idea of acting. He didn't want to be known just as Denzel's son, which seemed likely if he pursued acting. He wanted to make his own mark on the world, and for John David, the most obvious way was football. He was a star in high school.

"It was my independence card. And I started doing well with that and just kept going," he said.

He won a scholarship to Morehouse College, which led to a short career in pro ball, including a tryout with the St. Louis Rams, a stint in NFL Europa playing for the Rhein Fire in 2007, and then a few years in the short-lived United Football League. After an Achilles tendon injury, he turned again to acting. His football background got him a job on the HBO series Ballers opposite Dwayne Johnson, working for director Peter Berg.

During that time, he got a text message from Lee, asking him to read an out-of-print book — Black Klansman: Race, Hate and the Undercover Investigation of a Lifetime by Ron Stallworth, who infiltrated the Ku Klux Klan in Colorado. Washington had been recommended to Spike by Tonya Lewis Lee, the director's wife, who produced (along with John Legend) a movie called Monster costarring Jeffrey Wright and Washington.

When Washington got the BlacKkKlansman job, he immediately dove into Stallworth's compelling story.

"I just loaded myself up with as much background information as I could. That was paramount to me. I wanted it to be as accurate as I could make it," he said. That research included sitting down with Stallworth, now retired and living in Texas, and picking up some mannerisms, his sense of humor, his irascible and independent nature.

"He was the first black officer in [the Colorado Springs] department. That's a movie right there. I was intrigued to know about the mind-set of a guy who was able to make that happen, then to do what he did with such confidence," he said.

As an enterprising rookie detective, Stallworth called the local Klan chapter after it advertised in the local paper and asked to join. A white officer (played in the film by Adam Driver) was sent to actual meetings while Stallworth continued to work the phones – including, eventually, developing a long-term phone "friendship" with national Klan leader David Duke (Topher Grace).

Stallworth, impersonating a white racist, had lengthy conversations with Duke, often while amused officers listened in the background.

"Ron has a sense of humor. And there are aspects of the story that are funny. But we never thought we were making a comedy. The investigation that you see in the movie was always deadly serious," he said.

Stallworth was always well aware he was playing a role, and that helped Washington connect to the character.

"You're talking about a guy who had to be a lot of things back then. He had to be an actor, he had to get into character in order to try to get information. I think that helped me understand him a little bit," Washington said.

Stallworth's book is being reissued, and Washington is pleased to have a role in reviving his  story.

"I really excited for Ron having his coming-out party. I think he deserves to be celebrated for what he did. I think it's an important part of recent history," he said.

Washington traveled with the cast to France for the Cannes Film Festival, which he enjoyed mostly for the chance to share the atmosphere with his mother, Pauletta. As for Denzel, John David said he still doesn't like comparisons, but he couldn't quash a feeling of pride over something he saw in New York, where he's doing interviews.

"I got off the subway the other day, and I saw the BlacKkKlansman one sheet right next to the Equalizer poster. Side by side. That was amazing."