Well, if you ask me, I'd say she is pretty convincing.  Can you even tell this is Katy Perry? Here is some 'Unseen Footage' from her 'Birthday' video.  She said, "You have to have a trick up your sleeve if you're going to be a successful birthday singer."  She goes on to say, "I've got many tricks up my sleeve."  Towards the end of the video they even show you how they made her into 'Goldie.'

One thing is certain, she has some good marketing tactics.  Remember that HUGE gold semi that she had to promote her album?