NEW YORK (AP) — On the "Mad Men" premiere last summer, a boozy Pete Campbell hauled himself from his bachelor party to the door of Peggy Olson's modest Brooklyn apartment.

"I wanted to see you tonight," implored Pete, an overzealous ad account executive who, at that late hour, was gripped by panic at his looming marriage.

Peggy, the winsome new hire in the Sterling Cooper secretarial pool, surprised herself by letting him in.

Airing on AMC Sundays at 10 p.m. EDT, the Peabody Award-winning "Mad Men" now is in its second season. And it has kept Pete and Peggy entangled in multiple ways, none of them romantic and most of them hush-hush (including the child that Pete still doesn't know about).

Fortunately, things are much lighter between Vincent Kartheiser and Elisabeth Moss, who play that pair on the splendid '60s-era drama. In a joint interview, they tease each other, laugh a lot, and seem like pals.

Turns out Kartheiser (at 29, a former regular on "Angel," the spinoff of "Buffy the Vampire Slayer") and Moss (who is 26 and played presidential daughter Zoey on "The West Wing") had met before they got "Mad Men." A few years back, both took part in a filmmaking workshop.

"You had a prima donna actor," says Kartheiser in self-appraisal, then nods toward Moss magisterially, "and Miss Perfect."

"Two sides of the coin," chuckles Moss.

Kartheiser recalls a scene: "I had a disease called congenital analgesia, which means I couldn't feel anything. My character was always burning himself with cigarettes and saying, 'Whatever."'

"And I was supposed to be in love with you," says Moss with a grin.

On "Mad Men," they enjoy far more, um, dramatic leeway.

"At the beginning Peggy was definitely naive," muses Moss, appraising the distance she's come, "and I wouldn't say she's toughened up, but, instead, the problems hitting her now have become bigger. At first, it was learning to use a typewriter, and now it's a baby — with the father of the baby someone she works with."

But she's moving up in the agency. A quick learner, she's now helping create ad campaigns. And she's gingerly overcoming anti-female bias in the workplace — even from Pete Campbell.

Meanwhile, Campbell continues trying to win approval from Don Draper, the magnetic though tormented agency exec at the show's core. But Draper (played by Jon Hamm) hates him. Campbell, for all his skill in the advertising game, lacks people skills. He's sort of a jerk — isn't he?

"Well, it's unfortunate that you see it that way," Kartheiser tells the interviewer with mock indignation. "Some people just AREN'T as likable as others, no matter what they do. Pete Campbell does the same (stuff) as Don Draper, but Draper's way more likable, and gets away with things."

Of course, no sweeping term such as "likability" does justice to the series' world of characters, who, even as they all share screen time, emerge as complex individuals.

"Jon is the lead, and he always has something going on," says Moss. "But I don't think the rest of us feel left out, or that we don't get our moments."

"We trust Matt," says Kartheiser, meaning "Mad Men" mastermind Matthew Weiner. "I don't think anyone in our cast has any doubt that he always has the best story line in mind, and that's what we're there to serve."

"Yesterday he said to me, 'The next episode we're shooting is about objects,' and I said, 'OK,"' Moss marvels. "He always has this grand idea, and we're just lucky to be part of it."

Moss even feels lucky to have "carried" Peggy's "child." It was a shrewdly gradual plumping-up process that went unrecognized as anything other than weight gain, even by the unwitting mother-to-be — until, much to Peggy's shock on the season finale, she went into labor.

"Over seven episodes, I had four stages of padding and three stages of makeup," says Moss. Friends she hadn't seen in years watched the show and — shades of Kirstie Alley! — worried that she had an eating disorder. "But they didn't want to ask."

"Like: 'Did you quit smoking?"' chortles Kartheiser.

But that was last season (and 1960). Now "Mad Men" has progressed to spring 1962.

For Moss, who (like Kartheiser and most of the cast) wasn't born yet, it's a history lesson she is moving through.

"But I've learned more about the similarities than the differences between then and now," she says. "Usually, you look back on another era in terms of the milestones. But at the same time, people were just living their lives."

She might have added: That's where the unexpected drama unfolds, where "Mad Men" lives its life.