Awesome
Even though I don't care that much about Kate Perry she does have some interesting outfits unlike Lady Gaga who is just bizarre. Have to say though, really nice background. Looks pretty cool with some sparkles as well.
Also pretty nice signature drawn on as well. How long did you spend trying to do the signature? Do you use a tablet or something or just really good with a mouse and photoshop?
Kind of liking how she has a color waves just coming out and away from her as well. They look pretty nice and awesome.
The outfit and her expression make the drawing a pretty neat piece though. She just looks real cheerful and seems happy to be singing a song about kissing a girl and liking (probably a lot of people would want to kiss her).
Have to say though, overall you did a great job here.
Excellent.