AceShowbiz -

It's a daughter for Eva Mendes and Ryan Gosling. The actress gave birth to a baby girl on Friday, September 12 in Los Angeles. It's the first child for both the 40-year-old star and her 33-year-old actor beau.

"She's absolutely in heaven being a mom. She's never been happier,” a friend of the first-time mom's tells PEOPLE. "She and Ryan are just in awe of this beautiful person they created. It's a really special time for them."

Mendes and Gosling started dating in 2011 and were notoriously private about their relationship. They managed to keep her pregnancy under wraps until earlier this summer when she was seen sporting noticeable baby bump when stepping out in El Lay.

Back in February this year, she was rumored telling officers at the Transportation Security Administration checkpoint at LAX that she would not be able to pass through the body scanner "because she's pregnant," which she vehemently denied later on.

"It's so ridiculous," she said on Ellen DeGeneres' show. "It all started because I didn't want to go through the scanners at the airport. You know those X-ray scanners, which are really creepy? They basically see you naked, right? And not only that, but there's a radiation aspect to it, so I always opt out."