TV Guide reports that the actor will play a dentist named Hank in the fifth episode of the show, the latest project from Grey's Anatomy and Private Practice creator Shonda Rhimes.
Begley Jr. previously played Dr. Victor Ehrlich on NBC medical drama St. Elsewhere from 1982 to 1988. He also recently played a guest role on troubled legal drama Outlaw.
Off The Map will star Rachelle Lefevre and Jason Winston George, and is expected to premiere on ABC in 2011.