Keith Olbermann's First Guests: Michael Moore, Markos Moulitsas

Keith Olbermann revealed on Twitter that the first guests of his new show will be two members of his roster of high-profile contributors: Michael Moore and Daily Kos chief Markos Moulitsas.

Moore and Moulitsas were both regular guests on Olbermann's MSNBC show. (Recently, while on Lawrence O'Donnell's show, Moore even joked that he wanted Olbermann to return with him to MSNBC to host a show.) Both were named as contributors to the new edition of "Countdown" which launches on Monday night at 8 PM.

While Moore has popped up frequently on MSNBC in the past few months, Moulitsas has been banned from the network since a Twitter feud with Joe Scarborough in 2010.