Keri Russell says she and Matthew Rhys were having sex in trailers while still wearing their costumes for The Americans, including her wigs and pearls, as their on-screen partnership became a real relationship.

On Chelsea Handler’s Dear Chelsea podcast, in the episode released Oct. 8, Russell recalled falling in love while working together: “We were falling in love and staying up all night and having sex all the time and just wearing disguises.” She added, “It was so fun and sneaky, and sexy, and so good.”

The series cast them as Soviet KGB officers living undercover as an American married couple.

They’ve been together for 13 years and share a 10-year-old son, Sam. Russell also has 2 children from her previous marriage to Shane Deary.

Russell said she’s in no rush to marry Rhys. “I don’t need my last name to go away,” she said. “Like, I’m cool, if you want to be here, be here. If you don’t, that’s cool too.”