Kelly Osbourne says she's not engaged.

The 'Fashion Police' star was rumoured to be secretly betrothed to boyfriend Matthew Mosshart but Kelly is adamant her man has not popped the question.

Speaking on The Kyle & Jackie O Show on Australian station 2DayFM, she said: ''I'm not telling you guys anything. When I have a ring on my finger, then you'll know I'm engaged!''

While she remained tight-lipped about her love life, Kelly did not hold back on giving her opinion of Lady GaGa.

The 'Born This Way' hitmaker upset Kelly's mother Sharon after she criticised Kelly's fashion show, saying that it ''breeds negativity'' with its comments on celebrity's outfit choices.

Kelly, 28, didn't appreciate the comments but she still respects Gaga for her music.

She said: ''This is something that I still to this day do not understand, I used to be obsessed with her ... she brought history and fun back into music.

''When I got this hypocritical email that she put across on her Facebook, I was like oh my god, now I don't like you anymore, but I do respect her as an artist.''