NASHVILLE, Aug. 27 -- Dolly Parton's death has prompted a renewed look at the long and unlikely journey of I Will Always Love You, a song she wrote 50 years ago that went on to shape careers far beyond her own.

The track, first released in 1974, began as a private farewell to her mentor Porter Wagoner before becoming a global phenomenon through Whitney Houston's 1992 cover for The Bodyguard, according to the BBC.

Parton once said she wrote the song after realising she needed to leave Wagoner's show to pursue her own path, recalling that she told herself, "What do you do best? You write songs."

She described singing the song to Wagoner alone in his office, and remembered him telling her, "That's the best song you've ever wrote," before ...