Simon Cowell was a judge on American Idol from its inception in 2002 until his departure in 2010. He was known for his often harsh and critical comments to contestants, but he was also widely credited for helping discover and launch the careers of many successful musicians, such as Kelly Clarkson and Carrie Underwood. Cowell's departure from American Idol was a significant blow to the show's ratings, and he was replaced by a panel of rotating guest judges for the following season.