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Two of Hollywood's slimmest stars have a big, fat beef with one another.

LeAnn Rimes is feuding with Guiliana Rancic after the E! host and reality star commented on Rimes' talked-about weight loss.

Rancic and her husband Bill are set to open a new Italian restaurant in Chicago, where singer-actress Rimes' husband Eddie Cibrian is currently shooting his new series The Playboy Club. In an interview with HuffPost Celebrity, Rancic, 36, said she'd love to feed Rimes -- and fatten her up -- at the eatery.

"She lost a lot of weight from all the stress in her life," Rancic mused. "She seems a little thin right now, and I think she looks great when she's a bit curvier."

Immediately outraged, Rimes, 29, fired back via Twitter with a sarcastic invite. "@GiulianaRancic hey, we should go to dinner sometime. You get criticized all the time for how small you are. You can see just HOW much I eat and maybe put a stop to this crazy "shrinking" once and for all.....oh, & then we should workout together! Good luck with your restaurant!!!!," Rimes wrote.

The country singer then calmed down a tad and explained her rant. "I just don't appreciate her comments,' Rimes wrote, "So I really would love for her to hang with me, see who I am. I am a person, you know."