4 of 31:
Season 2 runner-up Clay Aiken enjoyed success as a recording artist following his time on 'American Idol,' due in part to loyal fans from the show known as 'Claymates.'
His debut solo album, 'Measure of a Man,' debuted at number one on the Billboard 200 albums chart in 2003. Aiken subsequently released 'Merry Christmas With Love' in 2004, 'A Thousand Different Ways' in 2006, 'On My Way Here' in 2008, 'Tried and True' in 2010 and 'Steadfast' in 2012. In 2004, Aiken embarked on a co-headlining tour with 'Idol' winner Kelly Clarkson, known as the 'Independent Tour' and in 2010 toured with Ruben Studdard as part of the 'Timeless' tour.
In 2012, Aiken became the runner-up on another competition series, this time as a cast member on 'The Celebrity Apprentice,' losing to talk show host Arsenio Hall. Aiken is also noted for his activism, founding the National Inclusion Project in 2003, serving as a UNICEF ambassador in 2004 and has spoke openly about his support of same-sex marriage. 'I think between 2003 and today, as we've seen with gay marriage polling, we've seen minds changing. We've seen more people becoming more open and understanding of homosexuality,' Aiken said in a 2012 interview with Bob Schieffer on 'Face the Nation.'
(Pictured: Clay Aiken performing during the April 18, 2013 episode of season 12 of 'American Idol.')
( Photo / Michael Yarish/ FOX)