The West Wing veteran Janel Moloney is joining the Showtime drama Brotherhood, which begins its second season on July 9.
She will appear in four episodes playing a woman who has an affair with ambitious local politician Tommy Caffee (Jason Clarke). The show also stars Jason Isaacs as Tommy's mobster brother, Michael.
Moloney is best known for her role as Donna Moss in NBC's The West Wing. Her other credits include the title role in the CBS TV movie Amber Frey: Witness for the Prosecution.