Some people just can't let it go.

Reality star-turned-celebrity fashion commentator Kelly Osbourne did not have nice things to say about pop star Christina Aguilera's weight gain on a recent "E! Fashion Police" segment.

Apparently, Osbourne thought Aguilera filled out a certain black dress just a little too much.

"Maybe she is just becoming the fat bitch she was born to be," Osbourne said.

Joan Rivers also threw in her two cents. "She looks like Snooki's Scandinavian cousin," she said. "It's a pretty dress but she's stuffed into it."

But Osbourne did not restrict her criticism to Aguilera's new curves.

"And she bought my house," Osbourne said, referring to Aguilera's purchase of the Osbourne home in 2008 for $11 million. TMZ reported earlier this year that Aguilera put the home on the market for $13.5 million.

Relations between Aguilera and Osbourne have been tense for years. The feud reportedly started when Aguilera mocked Osbourne at the 2003 MTV Europe Music Awards. This particular E! segment was not mentioned on either woman's Twitter account.

"She does have a beautiful voice. She just has a bad attitude to everything," Osbourne said of Aguilera.