The replacement for Katy Perry as an American Idol judge has been announced and it’s not the presumed pick of Meghan Trainor. In 2005, Carrie Underwood was the winner on American Idol’s 4th Season. That achievement launched the career of the multiple Grammy-winning country superstar. Now Underwood is set to return to familiar territory, as she is replacing Katy Perry as a judge on the upcoming season of American Idol. The new season of American Idol will kick off in the spring of 2025.