Little Gianni was born on Nov. 21, Hennessy's representative has confirmed.
He is the second child for the "Crossing Jordan" and former "Law & Order" actress and her husband, Paolo Mastropietro.
The couple also have a 4-year-old son, Marco.
No other details about Gianni's birth were immediately available, People.com said.
Senate Democrats to pull all-nighter on climate change
Dennis Rodman pledges to end trips to North Korea