Kelly Osbourne has never been a fan of Christina Aguilera, but the 26-year-old took their feud to a new level during a recent episode of E!'s Fashion Police. The video has since been removed from YouTube due to a copyright breach.

After Joan Rivers, 78, said Aguilera looked "stuffed into" a Givenchy LBD at an event in Munich, Germany last month (and likened her to "Snooki's Scandinavian cousin"), Osbourne chimed in: "Maybe she is just becoming the fat bitch she was born to be. I don't know. She was a c*** to me."

Back at the MTV Europe Music Awards in November 2003, the network aired a skit of Christina throwing darts at a photo of the British personality. When she took the stage, she mocked Ozzy's daughter as well, saying: 'Oh Lord, I didn't realise it was still Halloween.'

Kelly continued her tongue lashing, "She called me fat for so many f***ing years," she continued, "so you know what? F**k you, you're fat too."

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"She bought our house too, she lives in the house we filmed The Osbourne's in...Thank you!"

The Osbourne's were happy to take Christina's money for the sale of the house, given their recent problems with re-paying their tax.

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Osbourne opened up about her own weight struggles. "I took more hell for being fat than I did for being an absolute raging drug addict. I will never understand that," the reality star, who checked into rehab for drug and alcohol addiction three times, said.

The 5-foot-2 Osbourne, who once weighed "almost 160" pounds, recalled once walking down the street when "some horrible obnoxious teenager screamed out a car window to me, 'You're fat!' I went to my parents [Sharon and Ozzy] bawling, 'I would rather be called ugly than be called fat!'"

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After years of yo-yo dieting, Osbourne shed more than 48 pounds thanks to her 2009 stint on Dancing With the Stars -- and she's kept it off since!

"I just commit to half an hour a day. It doesn't seem overwhelming and I can handle that," she told Us in Oct. 2010. "I do half an hour on the treadmill and when I feel like doing more, I'll do a few sit-ups and some weights."