I just read that Adam Levine is in final talks to join the cast of American Horror Story season two. And yes, it's that Adam Levine. Maroon 5 frontman and judge/mentor from The Voice Adam Levine. Wild! Crazy! His role is being described as a modern day character, and one half of a couple called "The Lovers".
So as of right now we know of the following future cast members of AHS season two: Jessica Lange, Zachary Quinto, Evan Peters (yay!), Lily Rabe, Sarah Paulson, and (more than likely) Adam Levine.