Actor Jeremy Renner is a first-time father, according to a U.S. report.

The Avengers star's ex-girlfriend, whom Renner allegedly dated last year (12), gave birth to a baby girl on Thursday (28Mar13), reports

No further details were available as Wenn went to press.

The famously-private actor never even publicly confirmed the baby news when it broke in January (13), but a source told, "They used to date but it wasn't serious. He's being ultra-secretive about it."

Renner previously romanced aspiring actress Jess MACallan, but the couple split in 2010 after four years together.