(http://www.curiousonion.com/wp-content/uploads/2009/03/alyssa_milano.jpg)
For some reason your link is not showing. Here it is:
but who's the boss?
Don't think she's going to be an ex-wife; of course the first one, Alexis's mom, Meredith, was already cast and seen in Season 1. The second one is supposedly still his publisher. Paula (Debi Mazar) was the agent.
Ausiello reports she'll be a past love interest who Castle sees on her wedding day. Ausiello is right when he says things *are* picking up for Castle, as they are starting to get more high-profiled guests.
http://ausiellofiles.ew.com/2009/11/13/castle-scoop-alyssa-milano-charms-nathan-fillion/ (http://ausiellofiles.ew.com/2009/11/13/castle-scoop-alyssa-milano-charms-nathan-fillion/)