The professional dancers had become engaged on New Year's Eve and were planning to tie the knot at New York's Plaza Hotel next June.
Speaking to People, a representative for Smirnoff said: "I can confirm that this is true."
The spokesperson declined to give any further details and said that no statement would be issued.
A representative for Chmerkovskiy has yet to comment.
Smirnoff, 31, and 28-year-old Chmerkovskiy are currently preparing for the ninth season of the ABC reality show, which premieres on September 21.