Petraeus, who resigned in disgrace after an extramarital affair with his biographer came to light, was the only person on Walters' roster to remain a secret until her TV special aired Wednesday night.
"He is, without question, one of the finest officers and military minds of his generation," Walters said. "Then shockingly, he resigned this fall as head of the CIA because he'd had an extramarital affair with Paula Broadwell, his biographer. ... The story was irresistible -- the keeper of the nation's secrets unable to conceal his own."
Other celebrities on Walters' Most Fascinating list were "Argo" actor-director Ben Affleck, Olympic gold medalist Gabby Douglas, Britian's Prince Harry, reality TV star Alana "Honey Boo Boo" Thompson, "Family Guy" creator Seth MacFarlane, the British boy band One Direction, "50 Shades of Grey" author E.L. James, U.S. Secretary of State Hillary Clinton and New Jersey Gov. Chris Christie.