The ''Mad Men'' star proved he could do comedy when he hosted ''Saturday Night Live,'' and appears in December's ''The Day the Earth Stood Still''

Before Jon Hamm guest-hosted Saturday Night Live on Oct. 25, most people would’ve been surprised to learn that he’s a self-professed ”huge comedy nerd.” But by the time the Mad Men star busted out ”Jon Hamm’s John Ham: the ham you can eat in the bathroom,” it was clear that the real Hamm is — forgive us — a real ham. ”Most of my friends are comics,” says the 37-year-old St. Louis native, who spent his childhood checking out Bob Newhart, Bill Cosby, and George Carlin records from the library. ”But it’s not necessarily the thing I get tapped to do as an actor.”

That might have something to do with Hamm’s matinee-idol looks. And then there’s the simmering intensity he brings to Don Draper, 1960s Madison Avenue adman extraordinaire, whose dark and mysterious life took an even darker and more mysterious turn this year on the critically acclaimed but viewer-starved AMC drama. As he lost control of his carefully constructed world (wife Betty kicked him out of the house for cheating and then spent her days swigging red wine), Draper jetted off to California, where he went down the rabbit hole, only to be confronted head-on by his true self.

It’s a classically masculine and self-assured part. And given Hamm’s glowing reviews, it would normally lead directly to starring roles in studio movies. But the actor’s plate is surprisingly empty. His supposed overnight success (Hamm had already toiled for a decade in TV with recurring gigs on Providence and What About Brian) happened on the verge of a writers strike and the ensuing production slowdown. The poor guy didn’t even get to pick up his Best Actor Golden Globe at a ceremony. It was canceled — yet another casualty of the strike.

We will get to see his strong chin on the big screen Dec. 12 in the sci-fi/action remake The Day the Earth Stood Still, though it’s hardly an above-the-title role. ”I’m kind of the major exposition guy,” he says. ”I make sure that the two stars [Keanu Reeves and Jennifer Connelly] are introduced to each other properly, and I explain a lot of stuff.” Which is exactly what he doesn’t do as Draper, a man of few words — many of them lies. But Hamm would have it no other way. ”Don’s not a professional murderer,” he defends. ”He’s a professional liar. He’s a politician in many ways.” And that makes Hamm’s job especially juicy. ”It would be the most boring thing in the world to play a guy who’s just nice to everybody and only pets puppies and makes soup.”