Kevin Mazur, WireImage

Courtney Love is being sued by a fashion designer who claims she was defamed by the quirky singer/actress on Twitter.

Dawn Simorangkir (who designed the dress Love is wearing at left, with Bono and Scarlett Johansson) was accused via Tweet of being a "drug-pushing prostitute" who had lost custody of her own child and capitalized on the actress's fame, according to the lawsuit filed in Los Angeles.

Love also responded to Simorangkir's claims she owed her thousands in unpaid clothing bills with a rant that included: "She has received VAST amount of money from me over $40,000 and I do not make people famous and get raped too."

Now Love is set to answer novel civil charges brought by the designer in what The Hollywood Reporter describes as a first-of-its kind defamation lawsuit.

In depositions related to her lawsuit, Simorangkir charges that Love's viral outburst destroyed her business because the actress was fashion trendsetter, whose opinions mattered.

At the time of their dispute, Simorangkir was building her reputation as the "Boudoir Queen," the name of her then-nascent, vintage-inspired fashion label.

Legal analysts explained to the newspaper that the issue is whether celebrity tweets are interpreted by followers as fact, or merely opinion.

LeAnn Rimes, the Kardashian sisters and a stable of tweet-happy celebrities should be paying close attention to the case, which is set to begin Jan. 18.

Simorangkir is planning to present testimony from social media experts and include evidence of remorseful post-tweet emails and phone calls from Love as proof the star's comments to her some 40,000 followers were damaging.

"We don't believe there's any defamation," James Janowitz, an attorney for Love told the newspaper, who added that even if there was, "there was no damage."

Still, life would probably be a little less litigious for Love if she just stuck with her Twitter makeup tutorials.

Meanwhile, check out what Hugh Hefner's new fiancée, Crystal Harris, just flashed on Twitter.