Katy Perry always says a prayer before she goes onstage.

The 'Firework' singer is on her 'California Dreams' world tour and before stage time she always gets together with her stage crew to say a prayer to make the show go well.

She explained to Entertainment Weekly magazine: "I have this little box of prayers, but they're very small, simple one-line prayers, and I pull them out and read them out loud, and everybody either agrees or disagrees with them, and then we put our hands in a pile and dedicate the show to something funny or stupid."

While on the English leg of the tour she dedicated one show to folklore hero Robin Hood - renown for robbing from the rich and giving to the poor - in his hometown.

She added: "When we were in Nottingham, we dedicated the show to Robin Hood."

Katy also said she gets so used to doing shows, she has trouble adjusting to normal life and doing things for herself, because everything is usually taken care of by her tour manager.

She said: "You get so used to having transportation or a hotel room, and it becomes, 'Do I eat food now? How do I get to the movie theatre?' I'm a toddler. When I'm left at the airport to go home, everything stops functioning for me."