"American Idol" Season 1 winner saw tremendous success with her first single, "A Moment Like This," and has since released four albums, selling almost 10.5 million copies in the United States. In December 2010, Clarkson debuted a new song entitled, "You Still Won't Know What It's Like" at the "A Night for Hope" event in Nashville. Clarkson revealed through Facebook on Jan. 13 that her fifth studio album should be released in March.

Since finishing as first runner-up in the debut season of "Idol," Guarini has released three albums, but found greater success on TV. In 2007, the TV Guide Network signed him as permanent co-host for "Idol Wrap" and "Idol Tonight," and he's also a recurring commentator on MSNBC, FOX News Channel and the Style Channel. In 2010, Guarini made his Broadway debut as Carlos in the original Broadway adaptation of "Women on the Verge of a Nervous Breakdown."

Remember this second season semi-finalist who was disqualified due to topless photos taken earlier in her career? Davis didn't let that stop her, heading to stage for a successful career. Davis appeared in the Broadway musical "Rent" in 2003. In 2004, she played Effie in a West Coast touring production of "Dreamgirls," and starred with Ruben Studdard in "Ain't Misbehavin'" in 2008. Davis recently played the Fairy Godmother in Rodgers & Hammerstein's "Cinderella" in Berkeley, Calif.

Studdard was Season 2's winner and went on to release four studio albums, including his most recent, 2009's "Love Is." In addition to appearing on various television shows, he toured with Robin Givens in the comedy/drama "Heaven I Need a Hug." In 2008, he accepted the role of Fats Waller in a national tour of "Ain't Misbehavin'." Studdard returned to the "Idol" stage last March to perform his latest single, "Don't Make 'Em Like U No More." He and Season's 2 runner-up Clay Aiken toured last summer.

As season 2's runner-up, Aiken saw early success with his first album "Measure of a Man," and then released four more, including his latest, "On My Way Here," in 2008. Aiken made his Broadway debut playing the role of Sir Robin in Monty Python's "Spamalot" in 2008 and stayed with the musical until 2009. He recently toured with fellow "Idol" Ruben Studdard. Aiken created the National Inclusion Project in 2003, accepted a UNICEF ambassadorship in 2004, and in 2006 was appointed for a two-year term to the Presidential Committee for People with Intellectual Disabilities. The singer recently appeared in Washington, D.C. to speak on anti-gay bullying.

No one can forget William Hung's "Idol" audition for Season 3 — an off-key rendition of Ricky Martin's "She Bangs" — which gained the would-be singer widespread attention. His exposure on "Idol" landed him a record deal and surprisingly, he became the third best-selling singer from that season. He went on to make guest appearances on TV shows such as "Arrested Development" and "George Lopez."

As one of the youngest "Idol" contestants, Season 3 runner-up DeGarmo was signed to RCA Records after the "Idol" finale and released the single "Dreams" in 2004. She released one album, but found greater success on the stage, most recently as Sheila in the Broadway company of "Hair." DeGarmo returned to her home in Nashville in 2010. She's originating the role of Doralee Rhodes in the national tour of "9 to 5," which launched in September 2010.

Following her victory on Season 3, Fantasia released her debut single, "I Believe," which debuted at No. 1 on the Billboard Hot 100. She then released her debut album, "Free Yourself," which went platinum and garnered Barrino four Grammy nominations in 2006. She released a second album in 2006 and played the part of Celie in the Broadway musical "The Color Purple." Her third studio album, "Back to Me," was released last August. To promote the album, Barrino embarked on her first concert tour last fall.

Although she was eliminated during Season 3, Hudson has proven to be one of the most successful of the "Idol" contestants. She made her film debut in the 2006 film "Dreamgirls" and won an Academy Award for Best Supporting Actress, among many other honors. She also won a Grammy for her self-titled debut album in 2008. Tragedy struck that same year when Hudson's mother, brother and nephew were murdered. Taking a break, she resumed her public appearances in 2009 and had her first child. In 2010, Hudson became the spokesperson for Weight Watchers — and lost 60 pounds.

Winning the "Idol" title in Season 4 was only a launch pad for this award-winning country superstar. Underwood has sold over 12 million albums worldwide with her three multi-platinum records. She is a Grand Opry member and has had 13 No. 1 hit singles. In the summer of 2010, she married hockey player Mike Fisher, and she'll make her acting debut in the film "Soul Surfer," scheduled for release in 2011.

Constantine was the sixth-place finalist on "Idol" Season 4. After he left the show, he continued rocking as lead vocalist for his band, Pray for the Soul of Betty. He then went on to find success on stage and received a Tony nomination for his role in the Broadway show "Rock of Ages." In December, Constantine and girlfriend, former "Rock of Ages" co-star Angel Reed, welcomed the arrival of their daughter, Malena James Maroulis.

This Season 4 runner-up has recorded three studio albums since "Idol." In 2005, Bice charted at No. 2 on the Billboard Hot 100 with a rendition of "Inside Your Heaven." In October 2010, he guest-starred on the syndicated game show "Don't Forget the Lyrics!" and won the $50,000 grand prize for his charity, MusiCares. Bice married Caroline Merrin Fisher in June 2005, and they now have three sons and reside in Nashville.

At age 29, Hicks became the oldest contestant to win "American Idol." He signed a recording contract and put out his debut single "Do I Make You Proud," which hit No. 1 on the Billboard Hot 100. On June 6, 2008, Hicks joined the cast of the Broadway musical "Grease." After touring with the show for 18 months, Hicks performed in over 20 live shows. In 2009, he released his second album, "The Distance," on his own label, Modern Whomp Records. He recently appeared on TV's "Don't Forget the Lyrics!"

After his elimination from "Idol," Daughtry was given a record deal and formed a band called Daughtry, whose debut album sold more than a million copies after just five weeks of release (becoming the fastest-selling debut rock album in history). Daughtry is now the third most successful "Idol" contestant in terms of record sales, behind Kelly Clarkson and Carrie Underwood. At the beginning of this year, Chris tweeted that the band will soon be working on a new album. He lives with his wife, Deanna, and their four kids.

As "Idol" Season 5's runner-up, McPhee released her self-titled album, which debuted at No. 2 on the Billboard 200. Her second album, "Unbroken," was released in early 2010 and she also released a holiday-themed album last October. She's also established an acting career, co-starring in the comedy "The House Bunny" in 2008. Kat has also appeared on NBC's "Community" and will co-star in an untitled indie shark thriller, due in September 2011.

After being eliminated in Season 5, country singer Pickler released her debut album "Small Town Girl" in 2006. Her second album was released in 2008. In 2010, she was ranked as the 7th best "American Idol" alum and recently announced her third album will be produced by Frank Liddell. Pickler also eloped with songwriter Kyle Jacobs on New Year's Day.

Sparks was declared Season 6 winner at the age of 17, making her the youngest winner in the show's history. She followed her "Idol" victory with the release of her debut album in 2007 and a second album, "Battlefield," in 2009. She toured with the Jonas Brothers and followed that by making her debut on Broadway in 2010, starring as Nina Rosario in the Tony-winning Broadway musical, "In the Heights." In January 2011, it was reported that Sparks and John Legend were working on songs for her third album.

Sanjaya gained national attention on Season 6 of "Idol," advancing to seventh place with public votes, despite being poorly received by the show's judges, particularly Simon Cowell. After "Idol," Malakar made many TV guest appearances and has been commonly parodied in popular culture. He got to fifth place in Season 2 of the reality TV show "I'm a Celebrity...Get Me out of Here!" In May 2010, Seattle Weekly reported that Malakar was working as a singer for Pagliacci Pizza, a Seattle-based pizzeria chain.

As Season's 6 runner-up, Lewis released his debut album "A.D.D. (Audio Day Dream)" in 2007. His second album, "Heartbreak on Vinyl," was released in 2009. Lewis has also been supporting cancer research. In 2010, Lewis competed on "Don't Forget the Lyrics!" to raise money for the Seattle Children's Hospital, a charity that he's worked with for over 10 years.

As Season 7's "Idol" winner, Cook soon released a self-titled album in 2008, which went platinum. In January 2009, Cook announced he would be embarking on a national tour called "Declaration." Cook's eldest brother, Adam, who had battled brain cancer since 1998, died in May 2009. Though Cook was not there when Adam died, he had canceled several performances weeks earlier to see him and say goodbye. Cook's second album will be released in early 2011.

Archuleta began his singing career early, and at age 16, finished second in Season 7. In August 2008, Archuleta released "Crush," the first single from his self-titled debut album, which debuted at No. 2 and has sold over 900,000 copies worldwide. In October 2010, he released a second album, "The Other Side of Down," featuring the lead single, "Something 'Bout Love."

Prior to his Season 8 "Idol" win, Allen released a 2007 album entitled "Brand New Shoes" and post-"Idol," his self-titled album was released in November 2009. Allen is currently on tour with the band Lifehouse. He married his high-school sweetheart in 2008.

After coming in second in Season 8, Lambert released his debut album, "For Your Entertainment," in November 2009. The album debuted at No. 3, selling 198,000 copies in the United States in the first week. He kicked off his first solo tour in June 2010 and announced that he's already working on a second album, expected to be released in 2011.

As Season 9's runner-up, Bowersox has been going non-stop. Her debut album, "Farmer's Daughter," was released in December 2010, and she performed her title single on "The Ellen DeGeneres Show." Bowersox and musician Brian Walker were married in October.

Last year's "Idol" winner had a solo career before "Idol," releasing two independent albums called "So I'm Told" in 2007 and "Slumberland" in 2010. His post-"Idol" album, "Live It Up," was released in November.