American Atheist president David Silverman on Wednesday said Fox News host Bill O'Reilly had a very different personality on and off air.

"This is all about money, this is all about ratings," Silverman said on The David Pakman Show. "They bring me on because they think they'll get more ratings if they bring me on. [O'Reilly] wants good television, he wants good fire, he wants that battle. He wants to show his teeth and bring out his claws, and he wants somebody that will fight back."

"O'Reilly seems to be a cordial guy who is doing his job, which is to portray this horrible character on television," he added, unlike his Fox News host Sean Hannity, who didn't appear to be acting.

During a recent interview, O'Reilly told Silverman that Christianity was not a religion. Silverman said by claiming that Christianity was merely a philosophy, O'Reilly was attempting to undermine the separation of church and state.

"It's an attempt to justify inequality," he said. "We're a Christian nation so we deserve special rights -- that's one way to do it. He's doing it a different way. Christianity is not a religion so it is not bound by the separation of church and state. It is totally fallacious and he knows it."

Of the six Fox employees he spoke with, four were atheists or skeptical of religion, Silverman said. He also claimed at least one female Fox News host was likely an atheist, but refused to name any names.

Watch video, uploaded to YouTube, below: