The actress is pregnant and due in October, PEOPLE confirms. This will be the first child for both actors, who played parents in their 2012 drama The Place Beyond the Pines.
A friend of Mendes’s tells PEOPLE that while the actress had said in the past she wasn’t planning to get married or have children, “with Ryan things are different … she’s very independent but she’s content with her partner. She finally found the person she really wants to be with.”
Both Mendes, 40, and Gosling, 33, prefer to keep their relationship private, playing coy when asked about their love lives. But the expectant mom did gush about her beau’s acting abilities in the March 2012 issue of Marie Claire.
“He’s your dream costar,” she told the magazine of working with Gosling in The Place Beyond the Pines. “I have never felt so creatively satisfied on a film. He’s amazing.”
The couple more recently collaborated on Gosling’s directorial debut, Lost River, which premiered at Cannes this year.
– Michele Corriston with reporting by Jennifer Garcia