Facebook founder Mark Zuckerberg paid $65 million to two former Harvard classmates who claimed he stole their idea for a social networking site, a law firm has revealed.

The settlement amount in the suit waged by Cameron and Tyler Winklevoss, Zuckerberg's ex-classmates, was supposed to be confidential.

But a legal publication named The Recorder spotted the settlement sum in a newsletter put out by the Winklevoss brothers' legal team, the law firm of Quinn Emanuel Urquhart Oliver & Hedges.

Peter Calimari, an attorney for the California law firm, reportedly told the Los Angeles Times that although the firm had a policy not to discuss the case, public relations employees included the information in the newsletter and it couldn't be omitted in time to halt its disclosure.

The Winklevoss brothers charged in their lawsuit that Zuckerberg stole the idea for Facebook from their HarvardConnect Web site, which later became ConnectU. The ConnectU founders originally settled the case last February, but then contested the settlement and battled with their lawyers over legal fees.

The twins tried to argue that the settlement wasn't valid because it hadn't been signed by their father, Howard Winklevoss, a ConnectU shareholder and former professor of actuarial science at the University of Pennsylvania. But in June of last year, Judge James Ware of Federal District Court in San Jose rejected that argument, enforcing the February settlement and also dismissing ConnectU's allegations that Facebook had fraudulently misrepresented the value of its stock in reaching the settlement deal.