Scream star David and his girlfriend Christina McLarty welcomed son Charlie West Arquette on Monday, 28 April in Los Angeles.
A rep told People the tot weighed 8lbs 7oz and mum and baby are doing well. No other details have been released.
It's the second child for David, 42, who is also dad to daughter Coco, nine, from his marriage to Scream co-star Courteney.
David and entertainment reporter Christina have been dating since 2011. They announced their pregnancy in November last year, later revealing it would be a baby boy.
Well, it was actually David's ex-wife Courteney that let slip the baby's gender during a chat on US TV in January 2014, where she belated added: "I hope I'm allowed to say that!"
Telling Ellen DeGeneres how Coco had reacted to the news, she said: "Yes, she's really excited. At first she was nervous because it's a big deal. It's great. We all had dinner the other night, the whole family.
"It's a very unique relationship. Me and Christina and David and Coco, it's great."
Courteney is currently loved up with Snow Patrol rocker Johnny McDaid, who recently moved into her LA home.
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Celebrities who welcomed babies in 2014 in pictures:
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