Fox has begun casting for a second 13-episode installment of The Moment of Truth, a provocative new reality show, hosted by Mark Walberg (pictured), that gives away hefty amounts of cash to anyone who will admit deep, dark secrets in front of a national audience. The show’s second outing on Jan. 30 easily won its time slot among adults 18-49 (7.8 rating/19 share) and viewers (17.9 million) and is now the third-highest rated program of the 2007-08 season in the key demo behind American Idol on Tuesdays and Wednesdays.

Fox has ordered another 13 episodes of the show, in which contestants are a series of personal questions off-camera while they’re hooked up to a lie detector, but are not told how the machine registers their answers. The contestants then must answer some of the same questions before a TV audience, and if the answers are truthful, they win cash prizes. The next batch of fresh episodes could begin airing as soon as April, one Fox insider says.