While some stars may create a name for themselves by wearing fun fancy dress all the time - we're looking at you, Lady Gaga - others simply use it as a way of expressing themselves every so often.
Naomi Attwood of Grazia magazine said she has noticed this of Gwyneth Paltrow, who usually looks practically perfect in every way at red carpet events.
However, she occasionally lets her hair down and becomes someone else entirely. Last night (January 6th 2011) for example, she became a musician from the 1980s on Jimmy Fallon's talk show in the US, while she also donned a costume for Glee not too long ago.
Ms Attwood also pointed out that the Iron Man star dressed up as a rapper for the same programme last April and sported Madonna fancy dress to present the pop star with an award back in 2004.
She clearly has a creative streak she's dying to set free!
Perhaps Gwynnie could take a leaf out of Katy Perry's book, as she seems to be in costume quite a lot just lately.