Her fellow former Disney star Brenda Song, 23, is engaged to Cyrus's older brother, Trace, 22.
"I am very excited to say, last week I asked my girlfriend Brenda Song to marry me and she said YES!" the former Metro Station rocker Tweeted on Friday. "We are both very excited to be engaged!"
They aren't the only ones.
"@TraceCyrus can't wait for Brenda to be a Cyrus :)" Miley Tweeted Friday. "Couldn't be more excited about my 'sister in law to be' yay :)."
Song, who was recently photographed sporting some bling on her ring finger, appeared in The Social Network and models for Trace's clothing line, Southern Made Hollywood Paid.
"Miguel Aguilar / Nate Jones / Pacific Coast News