Brian Stack will be part of the Late Show with Stephen Colbert. Stack has left Conan, after 18 years of writing and appearing on O'Brien's show under its different names (Late Night, Tonight Show, Conan), as characters such as The Interrupter, old-timey traveling salesman, lounge singer Brian Lafontaine, the Devil, God, Zeus, offensive ghost crooner, voice of WikiBear, Audiencey Awards fashion critic, drunk partying Dumbledore, and many more. He also made appearances on 30 Rock and Parks and Recreation.
http://teamcoco.com/video/brian-stack-supercut
http://www.mstarz.com/articles/61136...t-18-years.htm
It makes me think of another writer/performer, Brian McCann, who spent 17 years on O'Brien's show before also leaving Conan and L.A. to return to New York, although I don't see anything suggesting he could join Stack at The Late Show, just an apparent lack of any present employment being listed on imdb and wikipedia. He was FedEx Pope, prudish audience member/Fun Hole guy, Preparation H Raymond, and a bunch of others including Minty the Candy Cane Who Briefly Fell On The Ground, with Stack singing his theme music.
http://teamcoco.com/mccann
Colbert was pretty much the only regular on-camera performer on the Colbert Report, unlike The Daily Show (from which The Colbert Report spun-off) with its 'correspondents'. Apparently that will not be the case on Colbert's Late Show. There's a lot of former Daily Show people who could presumably at least appear as guests or perhaps potentially as semi-regulars in comedy bits.