By Lynette Rice
Updated September 01, 2010 at 07:24 PM EDT

Image Credit: Chris Hatcher/PR Photos; Albert L. Ortega/PR PhotosShowtime announced today that comedian/actor Eddie Izzard and the Emmy-winning Frances Conroy will guest star on United States of Tara during its third season. Izzard will appear in eight episodes and Conroy in one episode opposite star Toni Collette (Tara Gregson).

Izzard will play Tara’s psychology professor who becomes fascinated with Tara while Conroy will star as Max Gregson’s (John Corbett) mother, a recluse with a compulsive hoarding problem. Production on season three begins mid-September in Los Angeles for a 2011 premiere.