Though the plot is still shrouded in Shondra-caliber secrecy, Variety says that "My Favorite Mistake," the two-hour Grey's Anatomy outing setting up an Addison-centric spin-off, will be directed by Michael Grossman, who was last behind the camera for "Great Expectations" (in which Burke and George popped the question to their respective ladies).

In addition to opening the door for Addison to possibly leave Seattle Grace, "My Favorite Mistake" (as previously reported here) will guest-star Taye Diggs and introduce Hector Elizondo ( Chicago Hope) as Callie's father. An exact airdate has not been announced by ABC, but the episode will serve as the 22nd and 23rd Grey's episodes (out of 24) of the season.