It looks as though Brandi Glanville isn't the only person on LeAnn Rimes' list of frenemies. Rumor has it that fellow country singer Carrie Underwood has been feuding with Rimes for years now as she has been "trash talking" about Eddie Cibrian's wife from behind the scenes.

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According to Star Magazine on Thursday, Underwood refused to play nice with Rimes while the two chart toppers were filming a CMA Country Christmas special last month. Insiders say that Underwood refused to speak to Rimes and even made waves when she found out her dressing room was next to her's.

A source tells the site, "She immediately had her people call the organizers to get her room switched. Carrie can't stand LeAnn. When they see each other, she puts on a friendly front, but she thinks LeAnn is desperate, unoriginal and a has-been. And LeAnn has no idea how Carrie really feels."

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What's more, Underwood hasn't forgiven Rimes for a remark she made after the American Idol alum won the Female Vocalist of the Year award at the CMA's in 2006. Rimes said at the time, "To see someone come in and win female vocalist that has been here for a very short time is a little disheartening."

The source further explains that the remarks were a "huge slap in the face for Carrie" and that it "showed LeAnn's true colors. She's waited eight years for an apology and has never gotten one. Carrie holds grudges. When they see each other out and at events, LeAnn acts like nothing ever happened, but Carrie will never forget."

So far, neither Rimes nor Underwood have made any public comments about their rumored feud.