The ad will play on Stewart's next to last show Wednesday. "Honestly, we couldn't afford the rate being asked for ads running on the last show," admitted FFRF Co-President Annie Laurie Gaylor, "but we're pleased to run the ad live one more time nationally before Jon retires."

In the 30-second ad, Ron Reagan identifies himself as "an unabashed atheist" who is "alarmed by the intrusion of religion into our secular government. That's why I'm asking you to support the Freedom From Religion Foundation, the nation's largest and most effective association of atheists and agnostics, working to keep state and church separate, just like our Founding Fathers intended. Please support the Freedom From Religion Foundation. Ron Reagan, lifelong atheist, not afraid of burning in hell."

Comedy Central has promised to pull out the stops on all its shows this week. The ad will run during the Aug. 5 show, which starts at 11 p.m. Eastern.

FFRF's TV spot has been refused by national CBS, NBC, ABC and FOX.