The daughter of Sharon and Ozzy Osbourne accepted a proposal from vegan chef Matthew while on a Caribbean holiday recently. They've been together for two years.
Taking to Twitter last night, she said: "Thank you so much to everyone for congratulating Matthew & I! We are the happiest couple on earth right now! Xoxo."
Kelly and Matthew met at supermodel Kate Moss' wedding to Jamie Hince in The Cotswolds in 2011.
Matthew is the brother of Jamie's The Kills band mate Alison Mosshart.
Kelly's family haven't publicly sent their congratulations yet, but no doubt they're thrilled by the news, as last year it was said they "loved" Matthew.
A source told Us Weekly: "Kelly's family loves her boyfriend. They think he's the nicest guy she's ever dated. He is very patient and down-to-earth."
Kelly's not alone! Check out some other engaged stars in our gallery below:
Copyright: Instagram Mark Wright