Barkin, an Emmy winner, will play Vera, a legendary real estate broker and Phil's new professional rival. Earlier this season, Phil (Ty Burrell) left his company to join a new firm, which will include new partner Tad, played by Greg Kinnear.
In contrast, Cannavale's guest spot will be a little lighter. The Emmy winner will play Louis, the former clown partner of Cam's beloved alter-ego, Fizbo.
Both Barkin and Cannavale's appearances on the ABC comedy are scheduled for early 2012, with Barkin possibly recurring.
Barkin currently appears in the indie film Another Happy Day. Cannavale, who most recently co-starred in Win Win, will recur on the upcoming season of Nurse Jackie as a tough new hospital administrator.