Kelly Osbourne says she's "unbelievably proud" of brother Jack following his engagement.
The reality TV star proposed to model-and-actress Lisa Stelly after just four months of dating and Kelly admits she couldn't be happier.
Writing on her twitter page, she said: "I guess you're not my little brother anymore. I'm so unbelievably proud of the man you have become! I'm so happy for you and Lisa!"
After accepting Jack's proposal, Lisa tweeted: "The most amazing man I've ever met asked me to marry him - and he wasn't joking! Crazy, right :) (sic)"
Jack has had his fair share of troubles after rising to fame on MTV fly-on-the-wall show 'The Osbournes', which followed him and his family including his heavy metal legend father Ozzy Osbourne, and he went to rehab for drink and drugs issues in 2003.
After getting sober he reinvented himself as a filmmaker, directing a video for his father's track 'Life Won't Wait' last year and producing a film about him, 'God Bless Ozzy Osbourne', earlier this year.
Lisa starred in Green Day's '21 Guns' music video.
Before getting together with Lisa, Jack had been linked to Kimberly Stewart and models Niki Cloyd and Sarah McNeilly.
- BANG! Showbiz