Holmes filed a $50 million lawsuit against American Media Incorporated, which publishes Star over a magazine cover that insinuated she was a drug addict.
Her attorney says the headline that read "Katie DRUG SHOCKER!" was untrue, unethical, unlawful and not supported by the actual story inside the magazine.
The cover featured a disheveled picture of Holmes, and the story itself claimed she was "trapped in a cycle of addictive treatments," based on interviews with former Scientology members.
Holmes says Star knew the story was false and published it to sell magazines.
In a statement, Star said it is standing by its story.
The Associated Press contributed to this report.