The couple welcomed a baby boy, on Saturday, April 4. They have named their newborn baby boy Theodore Vigo Sullivan Gillies, E! News reported.
He was delivered at 5 A.M. In Los Angeles and weighed in 8 pounds, 14 ounces and measured 20.5 inches.
News of Cook's second pregnancy was first reported in January this year.
"We're as happy as we were surprised by this wonderful news! We haven't slept since 2013 and welcome advice from all parents who survived Two Under Two," the 35-year-old actress and Gillies said.