Surprise, surprise: Rosie O'Donnell has countersued her onetime publishing partner Gruner+Jahr, which this week had filed a $300 million breach-of-contract lawsuit against her for departing her Rosie magazine on Sept. 18.

The former talk show host, 40, is claiming that G+J breached its contract and forced her to leave her 18-month-old magazine (which previously had been the women's magazine McCall's).

NBC News says O'Donnell is suing G+J, which is owned by the German media behemoth Bertelsmann group, for $300 million.

On Thursday, O'Donnell's attorney Mary Jo White said in a statement: "When all the facts come out in the course of litigation, we're confident that a court will find that Rosie's decision to terminate the agreement with G+J was justified by G+J's misconduct, and that the court will award her significant monetary relief."

O'Donnell, 40, was reportedly miffed when G+J brass installed a new editor in the face of swiftly shrinking newsstand sales of the magazine. The sales slump hit after O'Donnell had left her TV show and came out publicly as a lesbian.

"We don't talk about pending legal issues, but we are confident that we will prevail in court," a G+J spokeswoman tells Reuters.

Also on Thursday, Rosie magazine staff members were gathered by G+J executives to be informed about the questionable future of the publication, "only to be told that there's no news," a staff member told PEOPLE.com. "So we all drag on here."