Sources confirm to Us Weekly that the 25-year-old actress has been "talking about getting engaged" with fellow actor Boyd Holbrook.
"They've been by each other for a while, taking a lot of couple time," an insider told the magazine, adding that the two "moved into a place in Brooklyn a few months ago."
Olsen and Holbrook have been dating for two years after meeting on the set of their film Very Good Girls.
"There was great chemistry there," a source said at the time. "She really likes him."
News of the engagement comes two weeks after it was revealed that Olsen's older sister Mary-Kate Olsen got engaged to French banker Olivier Sarkozy. While Mary-Kate's twin, Ashley Olsen is not planning a wedding of her own, it was reported in February that she was dating Moneyball director Bennett Miller.