“I thought a lot about ‘Butch Cassidy and the Sundance Kid,’” director Kasi Lemmons said in a recent Dallas interview about making “Talk to Me,” her new film about Washington, D.C. DJ Petey Greene, whose streetwise style made him an influential figure during the ’60s and ’70s on R&B station WOL-AM. The statement seems odd until you realize that the film isn’t about Greene, played by Don Cheadle, as much as it’s about his relationship with Dewey Hughes (Chiwetel Ejiofor), the program director who hired Williams and later became his manager when his career took off.

“I didn’t want to do a biopic,” Lemmons (“Eye’s Bayou”) explained. “I wanted to do a movie in which Petey Greene was a character—and a very, very, very dynamic character—and [show] how important he was within the confines of the movie—to those people, that community. And how important he was to Dewey.

“But really it’s a movie about friendship—the friendship between two black men. Because I thought it’s very rare that we see a truly deep friendship between men. I really tried to be guided by what I call the basic story—the friendship. And so I did not do a kind of ‘who Petey Greene was,’ the Petey life story, because I was afraid of getting distracted by too much of it. I wanted to stay true to the movie that I was trying to tell. That, I think, is in some ways more dynamic than to ‘cradle to grave’ it, trying to get every event of a person’s real life in.”

“Talk to Me” falls into two parts, very different in tone. The first half is a raucous comedy that details Petey’s unlikely hiring at WOL and his rise to a kind of local stardom. “I honestly didn’t know a lot about radio,” Lemmons admitted, “and, of course, you’re intimidated when you have the confines of a DJ booth or a radio station. But I knew how I wanted it to feel. I wanted it to have a lot of liveliness. I wanted it to have a beat, the dialogue very snappy.”

But at the halfway point the mood changes abruptly with the arrival of news about the assassination of Martin Luther King, Jr., and the movie becomes darker and more intense. “It’s a great joy for a director,” Lemmons said, “it’s my favorite thing to do. That turn is one of my favorite things in the movie. I love that it comes out of nowhere, because that’s like life—you’re laughing one second, and then you find out something’s happened that rocks your world. I talked a lot to the actors about how I wanted it to feel: you can’t see it and then all of a sudden it’s on you. There’s a lot of bickering going on in these relationships, and then instantly something bigger happens, and those things are forgotten, because all of a sudden it seems ridiculously trivial.”

There were other happy memories about making the picture, Lemmons added. One was the attitude of the producers, who, she said, were “very, very helpful, but not at all intrusive. They let me do my thing.”

Another was working with a remarkable cast—not just Cheadle and Ejiofor but Cedric the Entertainer, Martin Sheen and Taraji P. Henson. Lemmons came to the project with the experience of “Eye’s Bayou” behind her (“the best directing school I could ever have gone to—the school of Sam Jackson, I call it,” she said with a laugh), and relished the thought of working with Ejiofor, whom she called “an amazing actor,” and Cheadle.

“I couldn’t wait to see him do [Petey],” she said. “A lot of actors wanted to play it. But as soon as I got the idea of Don in my head, that was it. And as soon as I saw him in wardrobe, with the wig, and he started the vocal quality—the vocal quality is very different from how Don speaks—I heard Petey and I saw Petey.”

And Lemmons is certain that the focus she brought to the picture—the friendship between Petey and Dewy—will make it a story to which everyone can relate. “Because I really believe that a lot of our life experience is universal,” she said, “and we can enter into lots of different kinds of experience.”