"The veteran actress will play a new U.S. Marshall in a two-episode arc One of the USA Network's biggest hits will have some high-caliber guest stars for its upcoming third season. According to The Hollywood Reporter, Allison Janney will guest star on In Plain Sight's third season.

Janney will play a newly-minted U.S. Marshall who doesn't see eye to eye with Mary (Mary McCormack). This just adds to Janney's growing workload, as she signed on for a recurring role in the Showtime pilot Shameless, which stars William H. Macy, and has also signed on for Matthew Perry's NBC pilot, Mr. Sunshine.

In Plain Sight's new third season will also feature guest-starring stints from Rita Moreno, Steven Weber, Tess Harper and Josh Cooke. Moreno will play Ralph's (Cristian de la Fuente} aunt who ends up helping with Mary and Ralph's wedding, Weber will play an FBI agent in a two-episode arc, who feels witnesses should be handled differently, Harper will play a relentless federal prosecuter and Cooke will play the first witness that Mary and Marshall (Frederick Weller) ever handled.

In Plain Sight, which stars Mary McCormack, Frederick Weller, Nichole Hiltz, Paul Ben-Victor, Cristian de la Fuente, Lesley Ann Warren, Todd Williams and Holly Maples, will return with its third season premiere on Wednesday, March 31.