Alessandra Ambrosio gives birth to a baby boy
"Welcome my son, can't wait to show u around this crazy place," Mazur tweeted Monday afternoon.
No word on what the little guy's name is yet, but the model told E! News in April that she wants something that works well in both Portuguese and English.
"It can't be too American or my grandmother won't be able to pronounce it!" she says.
The couple's new baby joins big sister, 3-year-old Anja.