AceShowbiz - Katy Perry has taken aim at Madonna for peppering her music, videos and performances with religious references, insisting she hates it when artists take spirituality "lightly". The "Firework" hitmaker is the daughter of two pastors and, despite her racy performances, is a dedicated Christian.

And the singer admits it upsets her when pop acts use faith as a gimmick for their gigs, blasting the "Material Girl" - who has had a notoriously strained relationship with the Catholic church - for daring to perform on a cross during her 2006 Confessions tour.

She says, "For me, spirituality is something very important and I don't like it when people take it lightly. At times, I don't understand why there are artists who play that card, like when Madonna gets up on a cross to sing."

And Perry's distaste for blasphemy has forced her funnyman husband Russell Brand to clean up his stand-up act. She adds, "Russell has made very blasphemous jokes in the past, but he's making fewer all the time because he knows that I am very sensitive about this subject."