People literally danced into these bashes; they must have been relieved to have changed into their party clothes! God knows, Katy Perry was surely pleased to shed her wings.

[Photos: Benjamin Lozovsky/BFA/REX/Shutterstock, Angela Pham/BFA/REX/Shutterstock, Neil Rasmus/BFA/REX/Shutterstock, Matteo Prandoni/BFA/REX/Shutterstock, David X Prutting/BFA/REX/Shutterstock]