The country singer almost "wrecked the car" when she heard the vocal powerhouse's 1992 version of "I Will Always Love You" — a song that Parton penned in 1973.

Country icon Dolly Parton was behind the wheel of her car in 1992 when she heard an unmistakable a capella vibrato on the radio — though it took a moment for the tune to register. “I thought, 'That sounds familiar — If I should stay,'” she recalled years later. "And it didn’t hit me. It was just one of those things where [you think], ’What is that?’ And, then all the sudden, when she started singing, ’I will always love you.’ I just about wrecked the car.” The song, of course, was Parton's number one hit, "I Will Always Love You," and the singer was none other than Whitney Houston.

Kevin Costner asked Parton if they could use the song in 'The Bodyguard'

According to Parton, actor Kevin Costner had previously asked her to send the song, which she penned in 1973 as a farewell to longtime mentor Porter Wagoner, to potentially be used in his 1992 blockbuster, The Bodyguard. It wasn't until that moment, however, that she'd heard Houston's version, which music producer David Foster rearranged for the film.

“Kevin Costner and his secretary are the ones that loved the song,” Parton explained. “They had another song that was going to go in that place, and someone had recorded the song they were going to use. They were just in a panic at the last minute. And so they asked me about the song. I sent it. I didn’t hear anything more.”

That was partly because, as Costner, who both produced and played Houston's love interest in the film, has said, executives at Houston's label, Arista Records, took some convincing. "I said, 'This is a very important song in this movie.' I didn’t care if it was ever on the radio," Costner recalled in 2008. "I didn’t care. I said, 'We’re also going to do this a cappella at the beginning. I need it to be a cappella because it shows a measure of how much she digs this guy — that she sings without music.'"

Dolly Parton's cover of "I Will Always Love You"

Dolly Parton's cover of "I Will Always Love You" from 'The Best Little Whorehouse in Texas' soundtrack

"I Will Always Love You" won Grammys 10 years apart

The rest is history. “I Will Always Love You,” which earned Parton a Grammy nomination when she re-recorded it for her 1982 film, The Best Little Whorehouse in Texas, also won Houston the 1992 best female pop vocal performance Grammy. The Bodyguard soundtrack as a whole nabbed two more golden gramophones that year and became the first album verified by SoundScan to sell more than one million copies in a single week. Since then, the album has racked up more than 45 million sales globally, making it the top-selling soundtrack of all time, per The Hollywood Reporter.

"When Whitney did 'I Will Always Love You,' I mean look what a grand song she made out of that simple, heartfelt, you know, song… it was just amazing," Parton has remarked. "Whitney is the one who took it worldwide and really made it a household word — or song, I should say — so I'll always be thankful to her for that."

In addition to Houston, the “Jolene” singer has also noted that she owes a great debt to both Costner and Foster as well: "I really feel like that song belongs to all of us… I thought God was looking out for me, that it was meant to be, because how lucky was I that that got to be such a huge song."

The Bodyguard soundtrack

Whitney Houston's version of "I Will Always Love You" appeared on 'The Bodyguard' soundtrack

Thanks to Houston's version, Parton was seen more seriously as a songwriter

The massive success of Houston's rendition also put Parton "in the forefront as a writer," as she's said. "I was just a girl with the big hair and big tits and a big personality, but I think that one kind of pointed a finger at me as a serious songwriter and the fact that it did so well and I was so touched by it and so honored by it that. That one will stand out in my mind forever."

After Houston died from accidental drowning in a hotel on February 11, 2012, in Los Angeles at age 48, "I Will Always Love You" played at her funeral. Hearing the track this time, however, brought a whole new wave of emotions washing over Parton — though they were just as intense as the ones she’d felt in her car back in 1992.

"[It] just shattered me to hear that song played under those conditions," Parton revealed in an interview shortly after Houston's tragic death. "I thought my heart was gonna stop. It just pierced me like a knife. It's just — I can't explain that feeling, to think that that was so final for her and that that was my words and my feeling — I would forever be so connected to her."

Garth Brooks: The Road I'm On

A&E will premiere a two-part definitive documentary highlighting the prolific career of Garth Brooks, the best-selling solo artist of all time. Garth Brooks: The Road I’m On will premiere over two consecutive nights Monday, December 2 and Tuesday, December 3 at 9 pm ET/PT on A&E. The documentary offers an intimate look into Brooks’ life as a musician, father, and man as well as the moments that have defined his decade-spanning career and essential hit songs.