Kelly Clarkson, the first winner of "American Idol," celebrated the 21-year anniversary of her victory. Clarkson, who has become one of the show's most successful contestants, reflected on the life-changing moment on social media. She expressed gratitude to her fans for voting for her and acknowledged the access and opportunities that winning the competition provided her. Since her win, Clarkson has sold millions of albums, won Grammy and American Music Awards, and launched her own talk show. Her latest album, "Chemistry," explores her relationship with ex-husband Brandon Blackstock.