It's no secret that Katy Perry used to be a backing singer for Christian alternative metal band P.O.D., inasmuch as the information is widely available and she have never denied it when questioned.
However, now that she's one of the biggest pop stars on the planet, she may shake her head at her former life.
Some eagle-eyed person has spotted Perry in the back of a P.O.D. live performance, when they played The Jay Leno Show almost ten years ago.
You can clearly see Perry - and hear her distinctive vocals - at various points in the below video, including around 2:06.
Watch it below: