Gia Zavala is the couple's second daughter together
Matt Damon has become a father for the second time, after his wife Luciana gave birth to a baby girl.
A spokeswoman for the 37-year-old star of the Bourne action movies said new arrival Gia Zavala Damon was "a healthy, beautiful baby girl".
His 32-year-old wife was also "doing great", the spokeswoman added.
The pair already have another daughter - two-year-old Isabella - together, while Mrs Damon has another daughter, Alexa, 10, from a previous marriage.
The couple met in 2003 when she was working as a bartender in Florida where he was filming Stuck On You.
They got married in New York in 2005.
Damon rose to fame after appearing in the 1997 film Good Will Hunting which he co-wrote and starred in with friend Ben Affleck.
The film earned them an Oscar for best original screenplay.
He later received critical acclaim for his work in films including The Talented Mr Ripley and Saving Private Ryan.
More recently, Damon has proved his popularity at the box office with the spy franchise The Bourne Identity, The Bourne Supremacy and The Bourne Ultimatum.