And the romantic proposal took place on top of Empire State Building, People magazine reported.
On Tuesday the Thor actress, 31, posted a picture taken on the skyscraper with a sweet caption.
“Top of the world with my love @peterfacinelli @empirestatebldg #Love #ES,” she wrote.
Dating rumors regarding the two started circulating in 2012, when the couple was seen holding hands.
This will be the second marriage for Facinelli, 41, who was married to Jennie Garth, and the first for Alexander.