No one is sure what this special announcement is going to be about just yet, but Katy Perry is supposed to make an announcement Wednesday afternoon around 4:30p central time on her Facebook page.

In another example of artists turning to Facebook over troubled MySpace for their Web 2.0 needs, Katy Perry will be visiting Facebook headquarters on Wednesday to make a "special announcement." (Billboard.com)

The speculation about this announcement is leaning toward some kind of concert announcement - whether a tour is going to be sponsored by Facebook or the streaming of a Katy Perry concert.  Either way, we'll find out after 4:30p on Wednesday!