Kelly Clarkson, Season 1, Winner
First single: "A Moment Like This"
Fun fact: Remember that kind of terrible movie musical Kelly starred in with Season 1 runner-up Justin Guarini, From Justin to Kelly? Well, she was legally and contractually obligated to be in it. Phew.
Jennifer Hudson, Season 3, Seventh Place
First single: "Spotlight"
Fun fact: You probably already heard, BUT Jennifer won an Oscar for Best Supporting Actress in 2007 for her role in Dream Girls. Remember when Simon Cowell told her she looked like "something you should wrap a turkey in"?
Carrie Underwood, Season 4, Winner
First single: "Inside Your Heaven"
Fun fact: Carrie received college credit from Northeastern State University in Oklahoma for her time on American Idol. It counted as an internship credit toward her mass communications degree!
Katharine McPhee, Season 5, Runner-Up
First single: "Over It"
Fun fact: McPhee does more than just sing — she made her film debut in the 2008 comedy The House Bunny, and in 2012 she landed a starring role in NBC's musical series Smash.
Jordin Sparks, Season 6, Winner
First single: "Tattoo"
Fun fact: Jordin was the youngest contestant, at just 17 years old, to win American Idol. Oh, and in case you missed it, she dated pop superstar Jason Derulo for three years.
Chris Daughtry, Season 5, Fourth Place
First single: "It's Not Over," with his band, Daughtry
Fun fact: Before making it big on American Idol, Chris auditioned for (and was rejected from) a different reality competition show in 2005, Rock Star: INXS. Looks like being nixed from that show worked out in his favor.
Adam Lambert, Season 8, Runner-Up
First single: ""For Your Entertainment," which was quickly followed by his second hit single, "Whataya Want From Me."
Fun fact: Adam is one of the few people to ever get a standing ovation from the show's toughest critic, Simon. Simon rose to his feet after Adam's rendition of "Mad World."
Kellie Pickler, Season 5, Sixth Place
First single: "Red High Heels"
Fun fact: American Idol isn't the only reality show Kellie has appeared on. In 2013, Kellie and her dance partner Derek Hough won Season 16 of Dancing with the Stars.
Fantasia Barrino, Season 3, Winner
First single: "I Believe"
Fun fact: In 2007, Fantasia appeared on Broadway as the lead, Celie, in the hit musical The Color Purple.
Phillip Phillips, Season 11, Winner
First single: "Home"
Fun fact: Before appearing on Season 11 of American Idol, Phillip worked full time at his family's pawn shop.
Simon Cowell, Seasons 1-9, Judge
Fun fact: In 2008, while Simon was judging on The X Factor, he was offered the opportunity to be the face of Viagra for £1 million. Simon was slightly offended by the offer.
Paula Abdul, Seasons 1-8, Judge
Fun fact: In 2011, during the ABC special 10 Most Fascinating People with Barbara Walters, Simon Cowell revealed that on the first two seasons of American Idol, Paula and Simon "couldn't travel on the same plane together. We really disliked each other that much." He blamed their constant bickering on Paula's "sexual tension" with him.
Randy Jackson, Seasons 1-12, Judge
Fun fact: Randy Jackson was the last of the three original judges to leave the show. Did you know that besides Randy, Simon, and Paula, there were eight other judges? (Ellen DeGeneres, Harry Connick Jr., Jennifer Lopez, Kara DioGuardi, Keith Urban, Mariah Carey, Nicki Minaj, and Steven Tyler.)
Ryan Seacrest, Seasons 1-14, Host
Fun fact: On the first season of American Idol, Ryan Seacrest had a co-host, Brian Dunkleman...he quit after the first season.