In mid-April, Mendes was spotted leaving a building in LA with a large bag to cover her baby bump.
The 42-year-old managed to keep her second pregnancy under the radar and gave birth to the child last month.
A birth certificate, obtained by TMZ, revealed about the baby, who has been named Amada Lee Gosling.
The document stated that she was born on April 29 at 8:03 am at Providence St John’s Health Center in Santa Monica, California.
Amada, which means “beloved” in Spanish, sounds familiar because it’s the middle name of their first born, Esmeralda Amada Gosling.
It happens to be Mendes’ grandmother’s name and the character she played in 2007’s We Own the Night. Mendes and Gosling, 35, fell in love while filming The Place Beyond the Pines.
They welcomed their first child together in September 2014, also a daughter.