LeAnn Rimes may be happily dating 'Northern Lights' co-star Eddie Cibrian, but the singer is still unhappily dealing with her beau's soon-to-be-ex-wife, Brandi Glanville. The singer, apparently tired of alleged accusations by Brandi, has filed a cease-and-desist letter addressed to Eddie's former spouse and is threatening a lawsuit if the letter is not responded to within five days, E! Online reports.

An anonymous source, speaking on behalf of Brandi, says the accusations are absurd. "Brandi has been nothing but nice to LeAnn," the source insists. "She let her kids to go Mexico with them, and she is genuinely happy that they like her. If they didn't, then she would be upset.

The allegations come from the time period before Eddie and Brandi called it quits, when LeAnn was accused of stalking Brandi's then-husband. A rep for LeAnn says the letter was sent only "after months and months of Brandi speaking about LeAnn in the press and telling lies. This is a reaction, and something she felt was necessary to do to protect herself."

LeAnn's former husband, Dean Sheremet, filed for divorce in 2009, when rumors of an affair between LeAnn and Eddie first surfaced.

Meanwhile, LeAnn is back in the studio, working on an album of love songs previously sung by male artists, with Vince Gill producing the new project.

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