The proud new mother took to Twitter to announce the happy news.
“We are overjoyed to announce the birth of our daughter. She is absolutely perfect,” Hilaria wrote.
Hilaria Thomas Baldwin, 29, shared the news about her pregnancy to Extra in February.
The actor, 55, who is already the father of 17-year-old Ireland Baldwin with ex-wife Kim Bassinger, said at that time: “It really is the most amazing thing, I’m lucky.”