From Dick Cavett in the Digital Age:

Theirs[Cavett, Muhammad Ali] was a close if unlikely friendship that lasted five decades. “Dick Cavett was the whitest of white guys in America,” The Rev. Al Sharpton says in the film. “But he gave blacks that had been considered outside of the mainstream like Ali a chance to be heard, and a chance to say what they wanted to say unfiltered, which was rare.”

One night in the 1970s, Mr. Cavett recalled, the phone rang in his renowned summer house, Tick Hall. It was Mr. Cavett’s wife, the actress Carrie Nye, who was at their place in the city.

“Darling?” she said.

“This ain’t ‘darling,’” said Mr. Ali, who had been invited for an impromptu visit and given the master bedroom. “This is the three-time heavyweight champion of the world, and I’m lying in your bed, watching your TV.”