The former Fashion Star host, 49, the hotel heir, 43, dated for two years before splitting in March 2012. Though Macpherson briefly dated financier Roger Jenkins post-split, she and Soffer reportedly rekindled their romance after the real estate developer injured his vertebrae in a November helicopter crash.
This will be the second marriage for Macpherson, who was married to fashion photographer Gilles Bensimon from 1986 to 1989. The Australian supermodel has two sons with ex-boyfriend Arpad Busson: Arpad Flynn, 15, and Aurelius Cy, 10.
Macpherson, who is the host and executive producer of Britain and Ireland's Top Model, has yet to comment on her engagement via Twitter. Calls to her rep were not immediately returned.