Her husband announced the happy news on Twitter: “Welcome Apollo Bowie Flynn Rossdale 2/28/14. Bowie and Flynn = [our] mothers’ maiden names.”
Back in January, Stefani, 44, revealed that she was expecting a boy.
“I was ready to hand over the crown. but I guess I am still queen of the house. #itsaboy #surroundedbyboys” she wrote at the time.
Stefani and Rossdale have been married for 11 years, and they have three sons together, newborn baby boy Apollo Bowie Flynn, Zuma Nesta Rock, 5, and Kingston James McGregor, 7.
Gavin Rossdale is also a father to daughter, Daisy Lowe, 24, from a previous relationship.