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.

80

The Real Thing" - Bo Bice

Hot 100 Peak: No. 56 (2006)

"This was my first single after 'Idol,'" says Bice. "To be able to work with Clive Davis and have him call the shots and hand me such a great song was incredible. Marti Fredericksen, who is still a friend, wrote the song with Kara DioGuardi. Little did I know she would later become a judge on 'Idol.'"

79

"I Want to Live" - Josh Gracin

Hot 100 Peak: No. 45 (2004)

Before Carrie Underwood, Kellie Pickler, Bucky Covington, Danny Gokey, Casey James, Scotty McCreery and Lauren Alaina, "American Idol" produced its first country star. Gracin was serving in the United States Marines when he appeared on the show and was still in the military when he signed with Disney’s Lyric Street Records. Gracin noted at the time that he was thrilled to be signed to the same label as his idols, Rascal Flatts. His first single, "I Want to Live," peaked at No. 4 on Hot Country Songs.

78

Stay With Me (Brass Bed)" - Josh Gracin

Hot 100 Peak: No. 47 (2005)

Jedd Hughes was a 19-year-old student from Australia when songwriter Terry McBride spoke to his class at South Plains College near Lubbock, Texas. "I performed a few songs and then all of the students performed," says McBride. "Jedd was phenomenal. His guitar skills were so good." Hughes moved to Nashville and signed to McBride’s publishing company. They wrote a number of songs for Hughes to record, but one didn’t seem right for him. "'Brass Bed’ was a big love song and we didn’t think it fit on his album," McBride explains. "After we wrote it, Brett [James] went and demoed it and the next thing I knew, it was being recorded by Josh Gracin." When it was released as a single, the title was changed to "Stay With Me (Brass Bed)."

77

"8th World Wonder" - Kimberley Locke

Hot 100 Peak: No. 49 (2004)

Within an hour of Billboard compiling the Hot Singles Sales chart for the week ending March 27, 2004, "Idol" executive producers Nigel Lythgoe and Ken Warwick were looking at a page proof rushed over from the Los Angeles office showing Locke's first single debuting at No. 1. Based on that chart success, they immediately booked her to perform her hit on the following week's results show.

76

"Don't Forget to Remember Me" - Carrie Underwood

Hot 100 Peak: No. 49 (2006)

A week before he wrote with Ashley Gorley and Morgane Hayes for the first time, Kelley Lovelace was sitting in his chair thinking up ideas and came up with the hook for this song, which the trio composed for Hayes to record. Ben Vaughn, who was at EMI Publishing at the time, called Lovelace to tell him he may have just gotten one of the biggest cuts of his life. "I didn't know who Carrie Underwood was," says Lovelace. "I had heard of her, but hadn't watched that much of the show. I started researching and realized what a great singer she was. Of course, she sounded phenomenal." When "Jesus, Take the Wheel" was released and soared to No. 1 on Hot Country Songs, the three writers realized that Vaughn was right.

75

"Mama's Song" - Carrie Underwood

Hot 100 Peak: No. 56 (2010)

Composed by the same four writers in the same session as her previous single, "Undo It," this song was very personal for Underwood as well as co-writer Kara DioGuardi. "Carrie was with her fiancé and I was getting married. My mother had passed away and Carrie has a very close relationship with her mother. We got on the subject of why there are all these songs for fathers and daughters. What about the mothers who changed our diapers?" "Mama's Song" came together in an hour. "I think everyone was crying when we wrote it," says DioGuardi, who wanted to play her advance copy at her wedding. "But I was afraid the DJ would put it on the internet."

74

"Because of You" - Reba McEntire w/ Kelly Clarkson

Hot 100 Peak: No. 50 (2007)

Two years after Clarkson took this song to No. 7 on the Hot 100, "Because of You" charted again as a duet between the first winner of "Idol" and Reba McEntire. The duo first recorded a song titled "A Lot Like You" for McEntire's "Duets" album but manager (and McEntire's husband) (and Clarkson's future father-in-law) Narvel Blackstock heard the two women rehearsing "Because of You" and suggested they record that for "Duets" instead.

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73

"Dark Side" - Kelly Clarkson

Hot 100 Peak: No. 42 (2012)

Songwriters busbee and Alexander Geringas were collaborating for the first time and spent their first day just getting to know each other. "We wrote a mediocre song," says busbee. "The next day Alex said, 'Let's write something for Kelly Clarkson.' I sat down at the piano and wondered what Kelly would want to say." What poured out was "Dark Side." "The concept popped into my head." The first demo had a female singer that was too slick for the song and the publisher suggested recording it again with a rock voice. "That demo was more pop-rock than Kelly's version."

72

"I Love You This Big" - Scotty McCreery

Hot 100 Peak: No. 11 (2011)

Ester Dean is known for penning songs for Mary J. Blige, Rihanna, Kelly Rowland and Nicki Minaj, so how did she end up co-writing for a country singer like season 11 winner McCreery? "I’m from Oklahoma," she says. "My father was in rodeo. It’s where I should be." "I Love You This Big" was originally written by Jay Smith and Ronnie Jackson from the point of view of a father singing to his kids and had to be revised by Dean and Brett James for the 17-year-old high school student.

71

"Two Black Cadillacs" - Carrie Underwood

Hot 100 Peak (to date): No. 41 (2013)

Written by Underwood with Hillary Lindsey and Josh Kear, this current single continues Underwood’s string of story songs with a dark edge. "Josh lives a few houses down from me," says Lindsey. "He’s like a mad scientist. He sits at home and comes up with ideas. He had the "two black Cadillacs" idea. It was a little more soulful so it was fun creating the story. Carrie took the video to another level."

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