American Idol's first winner, Kelly Clarkson sang "Piece by Piece" and brought Keith Urban to tears. The first Idol winner reunited with the show to sing "Piece by Piece," a heartfelt song about her father who left her when she was just a young girl. Clarkson wrote the song, while she was pregnant with her first child, expressing how good of a father her husband is and will be. Clarkson said, ?I?m pregnant, and it?s nostalgic, and I can?t believe it?s the last season."