Ryan Gosling and Eva Mendes
09/21/2011 at 04:50 PM EDT
and Eva Mendes
are making the most of their weekends together.
Two weeks after doing Disneyland
on a casual date, the pair were spotted hiking on the grounds of L.A.'s Griffith Observatory on Sunday – bringing a little extra star power to a place known for more celestial star-gazing.
"Eva wasn't dressed for the dirt road hike and she walked slowly in her sandals," an eyewitness says. "Ryan didn't seem to mind the slower pace and they … both looked very happy."
Gosling, 30, and Mendes, 37, recently filmed the drama The Place Beyond the Pines
together, and are now quietly dating off-screen. Gosling is currently filming The Gangster Squad
in L.A., where he's also clocking time with Mendes.
"[He] visits Eva at her house as often as he can," a source tells PEOPLE, adding that the two have been staying in – and hanging out.
"The couple have enjoyed many quiet nights with delivery food," says the source, "and have also been spotted on casual strolls in Eva's Los Feliz neighborhood."
Reporting by PERNILLA CEDENHEIM