Ashlee Simpson has announced her engagement to boyfriend Evan Ross.

The 29-year-old singer - who is mother to five-year-old son Bronx from her previous marriage to Fall Out Boy's Pete Wentz - began dating the 90210 star, whose mother is Diana Ross, last summer.

Ashlee revealed on Twitter: "My baby love and I are ENGAGED!!! Hallelujah Hawaii!!!" along with a picture of the happy couple.

Evan, 25, tweeted: "The love of my life said YES!!!!!!"

The actor - who has a part in the new Hunger Games movie, Mocking Jay: Part 1 - has previously described Ashlee as "the one".

He said in an interview last year: "I'm so in love and we've got amazing things going on. And we inspire each other."

Ashlee and Pete were together for five years before she filed for divorce in 2011. She also dated Boardwalk Empire actor Vincent Piazza from June 2011 to November 2012.