Ross is the son of Motown mega superstar Diana Ross.
He and Ashlee made their engagement announcement on Twitter Monday. Ross tweeted, “The love of my life said YES!!!!!!" along with a photo of the pair.
Simpson added, "My baby love and I are engaged!!! Hallelujah Hawaii!!!!!"
Ross is an actor and singer with numerous credits, and his first major role was in the film, ATL.
He recently was cast as Messalla in the upcoming The Hunger Games: Mockingjay—Part 1 and Part 2—scheduled for release in 2014 and 2015, respectively.
According to People, Ross hinted at the couple's future by stating, "She's the one" at The Hunger Games: Catching Fire premiere in November.