The Story of... 'I Will Always Love You' by Whitney Houston

'I Will Always Love You' will forever be known as one of the all-time great power ballads and movie songs.

Whitney Houston made the Dolly Parton love song her own in 1992, but did you know its fascinating history?

Who was the song written about? How did Whitney end up singing the song? Just how huge was the single's sales? Here's all you need to know about the classic: