The actors met while filming the Netflix series Gypsy. The two played husband and wife and turned their onscreen chemistry into a real life romance.
On Wednesday the couple strolled through the Musee d'Orsay and Tuileries Garden in Paris.
They stopped for a kiss before continuing on their way.
Naomi was previously with actor Liev Schrieber for 11 years before splitting in 2016. They share two sons together, Alexander and Samuel.
Billy has one son with actress Mary Louise Parker, William, 14. When asked about his new romance, Crudup told ET back in March, "I try to make it a point of not commenting publicly one way or the other about my personal life," he said. "I don’t particularly see the advantage of people knowing too much about me if I’m constantly trying to trick them into thinking I’m someone else."
What do you think of Billy and Naomi's PDA-filled walk? Sound off in the comments.