The reason? Neither one of them wanted to ruin a perfectly good friendship.
"We flirted with each other for 30 years, and it was much more electric," explains Rogers in an interview with Dan Rather, airing Tuesday on AXS TV. "I think once you consummate a relationship like that, it loses something. And she and I both believe that theory, so we did some massive flirting in front of the nation, but there was never anything more than that."
The pair has proved that theory right: 31 years after their "Islands in the Stream" duet, the friendship remains strong. In fact, just last year they dueted on the tune "You Can't Make Old Friends."
So what does Rogers, 76, love most about his longtime friend? "Dolly has no filter – if it goes in her mind, it comes out her mouth, she doesn't stop to think 'Maybe I shouldn't say this,'" he says. "She came over and put her arms around me and she said, 'Kenny, I just want you to know something; I could never sing at your funeral' and I said, 'So we're assuming I'm going first, is that what you're saying?' But that's what's so wonderful about her, if she thinks it, she says it."
See a clip from The Big Interview below, and catch the full program on AXS TV, Tuesday, Sept. 23 at 8 p.m. ET.