According to a report in People magazine, the 31-year old actor, who is filming The Proposal with Sandra Bullock, recently proposed to 23-year old Scarlett. The couple, however, have not set a wedding date.
Soon after the news of the engagement, Scarlett was seen sporting a ring at Monday night's Metropolitan Museum Costume Institute Gala in New York.
According to sources, Johansson was eager to 'show off her rock' (in the picture) with her Dolce & Gabbana gown.
Photograph: Getty Images