Kenny Rogers and Dolly Parton have undeniable chemistry, both in their music and their easy, flirtatious banter on and off screen. But while the two country music superstars admit they enjoy pushing the boundaries of their decades-long friendship, they insist they've never crossed a line, reports Gayle Thompson of The Boot.

"We flirted with each other for 30 years, and it was much more electric," Rogers tells AXS TV via People Magazine. "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 mega-hit "Islands in the Stream" duet, the friendship remains strong. In fact, just last year they performed another duet on the title track for Rogers latest album, "You Can't Make Old Friends," reports People.

Rogers, 76, says it's easy to explain Parton's appeal notes The Boot.

"If she thinks it, she says it," he says. "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 that.'"

As if to prove his point, the Country Music Hall of Fame member shared one of their recent conversations.

"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,'" he recalls, adding that he responded, "'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."