The actress and singer is engaged to boyfriend Evan Ross, who is the son of Diana Ross.
The pair announced the news Monday on Twitter and it was confirmed by Simpson’s publicist, Janet Ringwood.
Twenty-nine year old Simpson and 25-year-old Ross went public as a couple last summer.
Simpson was previously married to Fall Out Boy bassist Pete Wentz. They have a 5-year-old son, Bronx.
Evan Ross is an actor who will appear in the final two film installments of “The Hunger Games.”