Frances Conroy by Jean-Paul Aussenard/WireImage.com
has been tapped to join CBS'
Mike Birbiglia's Secret Public Journal
The new CBS comedy is based on comedian
's weekly life-chronicling blog of the same name. The sitcom will star Birbiglia as - you guessed it - an immature stand-up comedian living with his girlfriend in Brooklyn. Conroy, known best for playing Ruth Fisher in HBO's
Six Feet Under
, will play Birbiglia's mother. -