"He's here! He's ideal! 8lbs 2oz #wegotthis2018", Hilaria shared on social media, announcing their little one's arrival.
His name has not been revealed.
The couple have three children under the age of 5: daughter Carmen and sons Rafael and Leonardo.
Alec, 60 and Hilaria, 34 were married in 2012.
Just weeks ahead of the birth of her newborn son, Spanish beauty Hilaria revealed to HOLA! I wasn't upset about it but I was overwhelmed!
"I am the boss at home and everybody knows that". "That doesn't mean that we don't talk about things and I ask his advice and stuff like that". With that being said, Carmen was a little disappointed because she's been wanting a little sister! He's very big - I just found out today he's really big, like 90th-percentile big.