EXCLUSIVE: Finding a leading man can be difficult these days, but director Ben Affleck has found the perfect one for “Argo”: He cast himself.Affleck is set to star as Tony Mendez, the CIA exfiltration expert who created a fake Hollywood production to get six Americans who were hiding out at the Canadian ambassador’s out of Iran. Alan Arkin and John Goodman are in final negotiations to co-star in Warner Bros.’ Tehran hostage crisis pic as Hollywood producer Lester Siegel and Oscar-winning makeup artist John Chambers, respectively. George Clooney and Grant Heslov are producing the political drama through their Smokehouse banner along with David Klawans (“Nacho Libre”). Chris Terrio adapted Joshuah Bearman’s April 2007 Wired magazine article, titled “How the CIA Used a Fake Sci-Fi Flick to Rescue American from Tehran,” which told how the CIA and the Canadian government teamed to rescue six U.S. diplomats who’d been taken hostage at the American embassy by a group of Iranians in 1979. The CIA’s ruse involved the explanation that the six hostages were actually a Hollywood film crew scouting a movie titled “Argo,” and using those fake identities, they were able to flee the country. Affleck previously directed himself to both critical and commercial acclaim in WB’s “The Town,” which went on to gross more than $154 million worldwide. Helmer just started negotiations to direct a remake of French thriller “Tell No One” for Warner Bros and Universal, and he’s also producing “Father Daughter Time” for the studio. As a thesp, Affleck recently wrapped Terrence Malick’s next untitled pic. Affleck is repped by WME.