When Space Jam debuted in theaters on Nov. 15, 1996, it was an undeniable hit. The film told the story of Michael Jordan's return to basketball after being recruited by Bugs Bunny to help defend the Looney Tunes from a gang of aliens. (Jordan himself returned to basketball in 1995 after a brief attempt at baseball.) Combining the appeal of Jordan and Looney Tunes, the film quickly raced to No. 1, grossing over $90 million in the U.S. and becoming the third highest-grossing sports film of all time.

While Space Jam became a lasting hit -- its unfading appeal has even sparked rumors of a sequel starring LeBron James, who said it was one of his favorite movies growing up -- the soundtrack was just as successful. Peaking at No. 2 on the Billboard 200, the soundtrack went double platinum within two months of its release and featured the hit singles "For You I Will" by Monica, "Fly Like an Eagle" by Seal, "Hit 'Em High (The Monstars' Anthem)" by B-Real, Busta Rhymes, Coolio, LL Cool J and Method Man and R. Kelly's smash "I Believe I Can Fly."

"I said to myself, 'Man, I gotta do a song for this movie. And it's gotta be a great song -- something everybody can relate to, to touch the hearts of many,'" Kelly told ET at the time about writing the song.

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The ballad, which was the soundtrack's first single, was a remarkable shift for the musician, whose previous hits included "Bump n' Grind," "Your Body's Callin'," "You Remind Me of Something" and "Down Low (Nobody Has to Know)."

"He's always been seen as a R&B bad boy-type sex symbol," Hype Williams told ET in 1996 from the Chicago set, where he was co-directing the song's music video. The director, who helped define the MTV era, directed or co-directed 11 of Kelly's videos. "This is something that's a little bit different. It's more true to his character. It's got more to do with heart, got a lot more to do with religion and it's got a lot more to do with perseverance."

With lyrics like "If I can see it, then I can do it" and "If I just believe it, there's nothing to it," there were no doubting the song's inspirational message. "For the five minutes of 'I Believe,' you hear seasons change, tides turn and colts grow into stallions; Dorothy returns to Kansas, Moses beholds the Promised Land, Babar is crowned king of the elephants, Aeneas reaches Rome," Rob Sheffield wrote in his Rolling Stone review of the Kelly album R., which also featured the single.

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And it was on that album, which came out in 1998, that Kelly shared the mic with Celine Dion on "I'm Your Angel" and pushed his balladeering even further with "If I Could Turn Back the Hands of Time."

"I knew from the first melody that was gonna be the song that was gonna take me out of R&B and into another genre of music," Kelly told The Boom Box in 2013 while looking back on "I Believe I Can Fly." The song was a massive hit, reaching No. 2 on the Billboard Hot 100, earning three GRAMMY Awards and easily becoming Kelly's most successful single. (The song was held back from the top spot by Toni Braxton's "Un-Break My Heart.")

While Kelly ultimately returned to the sex that made him a hit, soaring ballads quickly became a staple of his career, helping make him the "King of Pop-Soul."