Not only does Katy Perry celebrate her 32nd birthday this week, but it's almost Halloween! What better reason to reach for a blue wig and heart-shaped bustier? With characters like Kathy Beth Terry and a selection of tour wardrobes to choose from, Katycats are simply spoilt for choice when it comes to dressing up like their candyfloss-coated idol. If you're having trouble picking this year, read on for 39 of our favourites. After all, every girl should dress up as Katy Perry at least once in their lifetime!