Ed Begley Jr. by Todd Williamson/ WireImage.com Ed Begley Jr. by Todd Williamson/ WireImage.com

Actor and environmental activist Ed Begley Jr. is adding another series to his already extensive resume. Begley has joined the new CBS comedy series Gary Unmarried (née Project Gary), which focuses on a newly divorced dad ( Jay Mohr) and his calculating ex, Allison ( Paula Marshall).

The St. Elsewhere alum will play the bright (yet exceptionally arrogant) therapist who attempts to counsel Gary and Allison through their split-up - all the while being engaged to the latter! (Larry Miller played the counselor in the original pilot.)

Begley's recent credits include the pot-fueled Pineapple Express, hitting theaters this week, and HBO's election drama Recount. - Gina DiNunno