Cameron and Tyler Winklevoss found a skeptical audience on Tuesday as they tried to convince a U.S. appeals court to let them out of a $65 million settlement over the founding of online social network Facebook.

The saga of the Winklevoss twins and Facebook CEO Mark Zuckerberg became silver screen lore with the release of the film The Social Network last year. It has long been a legal battle as well.

The 6-foot, 5-inch brothers, who sat in the front row at the 9th U.S. Circuit Court of Appeals on Tuesday, started a company called ConnectU while they were students at Harvard University. They say that fellow Harvard student and Facebook founder Mark Zuckerberg stole their idea. Facebook denies these claims.

The twins argue that based on an internal valuation at the time that Facebook did not disclose, they should have gotten more Facebook shares as part of the settlement to the dispute. Facebook argues it was under no obligation to reveal an internal valuation.

Senior Judge J. Clifford Wallace pointed out that the twins had several lawyers representing them at settlement talks, and that their father is a business expert.

That makes it difficult to believe that anyone took advantage of them, Wallace said.

I agree my clients were not behind the barn door when brains were passed out, said Jerome Falk, an attorney for the twins.

At one point the settlement was valued at $65 million in cash and stock, Falk noted during Tuesday's proceeding.

Goldman Sachs and Russia's Digital Sky this month snagged a deal to invest up to $1.5 billion in Facebook, valuing the world's No. 1 social network at roughly $50 billion -- exceeding the likes of Yahoo Inc and many other large, multinational companies.

(Reporting by Dan Levine. Editing by Robert MacMillan)