The Her star, 29, is expecting her first child with fiancé Romain Dauriac, PEOPLE confirms.
"I'm very happy," Johansson, 29, told PEOPLE in January of Dauriac, 31, a French journalist who manages a creative agency. "He's my buddy."
"Being engaged is an exciting time to enjoy and to really savor," she added.
Still, the actress — who was spotted wearing her vintage Art Deco ring back in September while promoting her sci-fi movie Under the Skin at the Venice International Film Festival — said she was in no rush to walk down the aisle.