This U.S. marshal now has her own posse.
Mary McCormack, who hunts down witnesses on In Plain Sight
, delivered her third daughter, Lillian, on Saturday morning, Sept. 10, her rep confirms to PEOPLE.
Lillian weighed in at 6 lbs., 15 oz. and is 20 inches long.
The actress, 42, and husband Michael Morris’s new arrival joins big sisters Rose, 4, and Margaret, 7.
McCormack – who gave PEOPLE a tour
of her trailer on-set – had her pregnancy
written into the storyline of her character Marshal Mary Shannon. – Julie Jordan