Baby Lucia was born Thursday, People.com reported.
Sorvino, 44, is married to Christopher Backus, 30. They are also the parents of Holden, 2, Johnny, 5, and Mattea, 7.
"We are thrilled beyond measure to have been blessed with our fourth precious, healthy child," the couple said in a statement issued to People.com.
Sorvino's film credits include "Mighty Aphrodite," "Mimic" and "Romy and Michele's High School Reunion."
Backus is an actor who will make his directorial debut with "The Sessionist" this summer.
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