Alessandra Ambrosio Gives Birth to Baby Boy!

And baby makes four for Alessandra Ambrosio's growing family! The supermodel's fiancé made the big announcement on Twitter yesterday.

OK! NEWS: ALESSANDRA AMBROSIO FLAUNTS HER BABY BUMP WHILE ON A HIKE

Jamie Mazur Tweeted, "Welcome my son, can't wait to show u around this crazy place." 

OK! NEWS: PREGNANT ALESSANDRA AMBROSIO REVEALS — "IT'S A BOY!"

Luckily the Brazilian model had a baby shower this past weekend in Brazil, just in the nick of time! She Tweeted, "So much fun at my little boy baby shower !! Now just have to wait for him to arrive!!"