This would be interesting! I actually think she would be really good.
From Hollywood Reporter: Sources tell The Hollywood Reporter that Katy Perry is in active talks to sign on as a judge of the new American Idol, set to premiere in 2018. Perry's arrival on Idol would mark the first on-camera puzzle piece, as negotiations continue over whether former Fox host Ryan Seacrest will be able to reprise his old gig on top of new duties with Live With Kelly and Ryan and his radio show. (An ABC rep declined to comment on Perry.)