"We are ecstatic to welcome @katyperry as a judge on ABC's #AmericanIdol!" the show's Twitter account said Tuesday.
"SO thrilled @ABCNetwork is bringing back @AmericanIdol, and I'm bringing it back to the MUSIC [eye emoji] you at auditions," Perry tweeted.
American Idol ran 15 seasons on FOX, ending in 2016. ABC confirmed last week it is bringing the singing competition show back in 2018, but it hadn't indicated until now who might host or judge it.