Chart Listings: Top 100 American Idol Hits of All Time +Their Untold Stories

As "American Idol" celebrates its 500th episode & Season 13 comes to a close, here’s our countdown of "American Idol" alums’ biggest Hot 100 hits ever – and the untold stories behind the songs.

When “American Idol” premiered on Fox-TV on June 11, 2002, it was far from certain that the “Search for a Superstar” (the show’s subtitle) was going to produce one. Music critics didn’t give the series much credibility and radio did not go out of its way to play songs by “Idol” finalists. The industry should have known better, based on the success of “Pop Idol” in the United Kingdom. The first of that show’s two seasons did produce two superstars, in Will Young and Gareth Gates. Young’s first record, “Anything Is Possible” / “Evergreen,” became the fastest-selling single in U.K. history and is the best-selling single of the 21st century. Gates’ first release, a remake of “Unchained Melody,” debuted at No. 1 on the official U.K. singles chart and was certified double platinum. The stage was set for similar success in America but there was no guarantee.

Then along came Kelly Clarkson, though the singer from Burleson, Texas, was not an obvious winner in the early days of season one of “American Idol.” Executive producer Nigel Lythgoe says, “Justin Guarini and Tamyra Gray, we all said right from the beginning, those two. Tamyra was going to win. Kelly didn’t come through. The only thing that stood out was her humor. It was only when we got into the top 10 that all of a sudden, [when Kelly sang] people would stand there open-mouthed.”

Clarkson demonstrated her sense of humor by switching places with Randy Jackson during her audition, but later, when she walked out on the set for the first time, Jackson leaned over to Paula Abdul and said “Who is that? Who is she??” Debra Byrd, vocal coach on “Idol” from season one to the beginning of season 11, explains, “They didn’t remember her. Kelly later said that was her fault. She had changed her look and her hair. But she just wasn’t on their radar.”