updated 07/10/2014 AT 2:00 PM ET
•originally published 07/11/2014 AT 8:00 AM ET
Hey, girl! Or, boy!
“They literally could not be more excited,” says the source. “She’s feeling great.”
This will be the first child for Gosling, 33, and Mendes, 40, who began dating in 2011 and, the following year, played parents in the dramatic film The Place Beyond the Pines.
The pregnancy wasn’t necessarily surprising to the actor’s friends. “Ryan adores kids. He has such a way with them,” an insider told PEOPLE last year. “He loves being around kids and can’t wait to be a dad.”
So, what makes Gosling and Mendes click?