A spokesperson for E! released a statement on Friday (27 February) to confirm that Kelly is leaving the series after five years.
The news comes just days after feisty Kelly threatened to quit the show after a 'race row' erupted concerning comments her co-presenter Giuliana Rancic made about actress Zendaya.
In a press release, E! said: "Kelly Osbourne is departing E!s Fashion Police to pursue other opportunities, and we would like to thank her for her many contributions to the series over the past five years, during which time the show became a hit with viewers."
Although the statement goes on to say that "no decisions have been made on her replacement", rumoured names already include Khloe Kardashian.
Earlier this week, 30-year-old Kelly had threatened to leave Fashion Police over a joke made by her co-host Giuliana Rancic while covering the Oscars red carpet.
She had joked on-air that Disney star Zendaya's dreadlocked hair smelt of "weed" and "patchouli", before issuing an apology to viewers.
At the time, an unhappy Zendaya herself wrote a lengthy Instagram post in which she said: "There is a fine line between what is funny and disrespectful.
"Someone said something about my hair at the Oscars that left me in awe. Not because I was relishing in rave outfit reviews, but because I was hit with ignorant slurs and pure disrespect."
Kelly herself tweeted: "I'm giving everyone involved 24 hours to make it right or the world will hear how I really feel. Contractually I'm not allowed to speak!
"I DID NOT MAKE THE WEED COMENT. I DO NOT CONDONE RACISM SO AS A RSULT OF THIS IM SEREIOULSY QUESTIONONIG STAYING ON THE SHOW!"
After the news about Kelly leaving the show became public knowledge this weekend, mum Sharon tweeted a public message of support to her daughter.
She said: "@KellyOsbourne, I am so proud of you. You can never be bought. You always wear your heart on your sleeve. #ProudToBeYourMum."
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