Kelly Osbourne slams Rihanna on twitter?

Kelly Osbourne has slammed Rihanna on twitter.

The 'Fashion Police' host appeared to suggest the 24-year-old singer should get a ''sense of humour'' as she defended her co-star Joan Rivers after the comedienne recently blasted Rihanna when the Bajan beauty said she still ''loves'' her ex-boyfriend Chris Brown.

Kelly wrote on twitter: ''W/ the greatest of respect 2 a young lady of whom I love please get a sense of humor @Joan_Rivers paved the way 4 all us opinionated ladies! (sic)''

The 27-year-old presenter's comments come after Rihanna recently explained in a TV interview with Oprah Winfrey that she still has feelings for Brown, who she split from in February 2009 after he assaulted her, saying: ''We love each other and we probably always will.''

But after watching the show Joan took to her twitter account to describe the 'We Found Love' hitmaker as an ''idiot'' for making such heartfelt comments about Brown.

She wrote: ''Rihanna confessed to Oprah Winfrey that she still loves Chris Brown. Idiot! Now it's my turn to slap her.''

Rihanna then responded, in a message which has now been deleted, saying: ''Wow, you really do get slow when you're old, huh?''

And the war of words continued with Joan adding: ''Honey, @Rihanna, everyone knows: If he hit you once, he'll hit you again. Read the statistics. PS - Love to have you on Fashion Police! (sic)''.