The former 'Fashion Star' host, 49, dated the hotel heir, 43, for two years before splitting in March 2012, reported Us magazine.
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.