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.

50

"I Told You So" - Carrie Underwood ft. Randy Travis

Hot 100 Peak: No. 9 (2009)

Travis first appeared on the Hot 100 in 1998 but he never reached the top 10 until his duet with Underwood peaked at No. 9 in 2009. He first cut his self-penned "I Told You So" in 1983, on a live album he recorded as Randy Ray. A studio version appeared on his 1988 album "Always & Forever" and a single went to No. 1 on the country chart. It was one of Underwood's favorite songs growing up and she recorded a cover version for her album "Carnival Ride." First issued as a solo single, it was quickly followed by a duet version that paired Underwood with Travis.

49

"I'll Stand By You" - Carrie Underwood

Hot 100 Peak: No. 6 (2007)

Billy Steinberg was a huge fan of the Pretenders and Chrissie Hynde and dreamt of working with her but thought she was too self-contained to collaborate with outside writers. "Tom Kelly and I threw out the idea that we would like to write for her and she said she wanted a hit and was open to writing with us." The result was "I'll Stand By You," which peaked at No. 16 in 1994. Some 13 years later, Underwood's single debuted at No. 6 after she performed it on the first "Idol Gives Back," during the sixth season of the Fox-TV series. Over 300,000 downloads were sold during the brief period the song was available, with all profits going to charity.

48

"Feels Like Tonight" -Daughtry

Hot 100 Peak: No. 24 (2008)

Chris Daughtry's initial reaction to "Feels Like Tonight" was that he didn't want to record it. "But I ended up loving the song. It has such a great melody with a simple lyric. Once I started singing it, I realized it's actually a fun song to sing." It was the fourth single to chart from Daughtry's debut album and the first not to list Chris in the writing credits. It was also the only single from the album to miss the top 20 of the Hot 100, peaking at No. 24.

47

"I Do Not Hook Up" - Kelly Clarkson

Hot 100 Peak: No. 20 (2009)

Katy Perry and Greg Wells were working on this song before Perry signed with Capitol, and then it was finished much later. "Katy came over to my house and we sat on the kitchen floor and wrote the rest of it," says Kara DioGuardi. "Kelly changed one of the lines. She wouldn't say, 'keep your thing in your pants.'" The new lyric: "Keep your hand in my hand."

46

"Spotlight" - Jennifer Hudson

Hot 100 Peak: No. 24 (2008)

After her success with "Dreamgirls," Hudson was signed to Arista. The first single from her debut album was written by Ne-Yo with Mikkel Eriksen and Tor Erik Hermanson, the two members of the Norwegian production team known as Stargate. "Spotlight" spent two weeks at No. 1 on Hot R&B/Hip-Hop Songs. Hudson is only the second Idol to top this chart, after Fantasia, who did it with "When I See U."

45

"Undo It" - Carrie Underwood

Hot 100 Peak: No. 23 (2010)

Kara DioGuardi, Marti Frederikson, Luke Laird and Carrie Underwood wrote "Undo It" and the follow-up, "Mama's Song," in one five-hour stretch. "Undo It" was born in DioGuardi's bathroom. "I had this idea in the shower, put it down on my Dictaphone, brought it in and Carrie really liked it," says DioGuardi. The session marked the first time DioGuardi met Underwood and they spent part of the five hours just getting to know each other. "It's important to talk and make sure you have a common denominator, that you've gone through similar experiences," says DioGuardi. "We ordered some wine. We needed to vibe, and open up a dialogue on subjects everyone's been through."

44

"So Small" - Carrie Underwood

Hot 100 Peak: No. 17 (2007)

Luke Laird remembers the second day he got together with Hillary Lindsey and Carrie Underwood to write songs. "Hillary was playing mandolin and I was playing guitar." Lindsey explains, "I can't really play the mandolin but I can make a sound. I started playing a lick while Luke was on the phone and he pointed at me to keep playing so I wouldn't forget it. We had a melody but no idea. A friend's father had passed away and as we were talking, someone said, 'That's what matters. It makes everything else so small.'" Laird continues: "I woke up in the middle of the night, put on my headphones, listened to it and thought, 'This feels really special.'"

43

"Good Girl" - Carrie Underwood

Hot 100 Peak: No. 18 (2012)

Underwood was in Los Angeles when she met with Ashley Gorley and Chris DeStefano for a writing session. Gorley came up with the title that morning. "We worked through two or three different grooves with that title," he remembers. "Then we started something else, but came back to it. We got the 'Good girl, no good for you.’ We kept coming up with cool sections of the song. Most songs are verse, chorus, verse, chorus, bridge, chorus. This is more verse, pre-chorus, chorus, post chorus and then something else and another part of the chorus. It was different, especially for country. We were writing over the electric guitar licks and drum patterns you hear on the record. Being in L.A. probably made us go a little more out of the box. But I’m not afraid to rock with her. She crushed the song."

42

"Blown Away" - Carrie Underwood

Hot 100 Peak: No. 20 (2012)

Listening to the thunderstorm and rain sound effects on this song, it would be easy to assume they appear on the track because of the lyrics. But actually, it's the other way around. Songwriters Chris Tompkins and Josh Kear, who also composed "Before He Cheats" for Underwood, wanted to write songs for her fourth album and met at Tompkins' office in Nashville. "I have a bank of sound effects on my keyboard and sometimes I'll goof off and Josh will roll his eyes at me," says Tompkins. "We messed around with this track, with drums and a string arrangement. I looped off thunderstorms and rain, all these sound effects. Then we wrote the verse." When they came up with, "There's not enough rain in Oklahoma to wash the sins out of that house," they realized,  "This song really wants to be a Carrie Underwood song.  It was a little dark and poppy. It had every characteristic of a Carrie song."

41

"Inside Your Heaven" - Bo Bice

Hot 100 Peak: No. 2 (2005)

When this single debuted at No. 2 on the Hot 100 the week of July 9, 2005, Carrie Underwood's version of the same song fell 1-3. It was the first time in the history of this chart that the same song occupied two of the top three positions. "I had to stand toe-to-toe with Carrie on the finale, singing the same song," says Bice. "Her version was so impressive and that's definitely when I realized what a tough competition this was."

 

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