Kirstie Alley managed to turn her battle with her weight into TV gold, but now the "Fat Actress" is in a war with Rosie O'Donnell. The former talk show host is fuming about America's newest diet queen and only "Extra" knows why.

"I'm telling you right now I'm 218 pounds," O'Donnell insisted to us. "Kirstie Alley is not 210. She's a lying sack of s***."

Rosie railed against Kirstie at a women's health benefit Monday in New York, just like she did on "Extra" after Kirstie went public about her poundage. "At least tell the truth," said O'Donnell. "She's got to be at least 248; you know what I'm saying?"

And weight watcher Rosie is refusing to give up her Kirstie campaign easily. She's actually posted multiple criticisms on her official Web site.

People magazine Senior Editor Cynthia Sanz says it's the battle that won't die. "Both Kirstie and Rosie are really well known for being outspoken and saying exactly what they think," she said.

But Kirstie's not letting a little beef like this get in the way of her success. Her show is a bona fide hit and her Jenny Craig diet campaign is in full swing. But Rosie warns, don't let the facts get lost in the fat.

"I just feel as though Kirstie, who I think is very brave and bold, should admit that she is not 210 because the fatties of America know," Rosie insisted.