She said: "I will be especially naughty under Russell's influence. I've worn things recently that aren't appropriate for this - sorry mom, sorry dad."
Katy also admitted she won't be concerned if she exposes her breasts in any of her revealing outfits in Berlin tonight.
She added: "MTV asked me back because I have this no fear attitude. I don't care if I do fall over or if a boob does fall out.
"I've gone for less costume changes this year but less clothing too. It's all a bit naughtier, with lace, crystals and lots of boobie things. It's sexy. I'm highlighting what God gave me - what mama made."
Source: M&C