As far as I can tell, the only wedding that has been announced is the wedding of Bruce Wayne and Selina Kyle. So, how does the Joker know that Batman is marrying Catwoman? Unless the Joker already knows that Bruce Wayne is Batman? What am I missing?
Also, Selina Kyle's infatuation with Batman isn't a secret - I don't think. Won't some of Batman's rogue's gallery make the connection that the man she is marrying is probably Batman?