Mad Men was built on three things: Jon Hamm, excellent writing, and a mountain of fake cigarettes.

Hamm, who starred on all seven seasons as hotshot creative director Don Draper, learned quickly how important it was that those cigarettes the core cast smoked throughout each episode were indeed fake, a.k.a. nicotine-free. But recently, he humorously recalled what happened when an unnamed clutch of younger actors on the show insisted they opt for the real things.

"I'm glad I'm still alive, basically, because of the amount of cigarettes I smoked," Hamm joked on a panel with his Mad Men costar John Slattery on Saturday at Austin's ATX TV Festival. "Some of the younger actors," Hamm recalled, wanted to "smoke real cigarettes, because, 'We really want to feel it and do it.' I was like, 'Let me know how that goes.' Within three days they were yellow and sallow. It's a terrible thing to do."

Fargo series creator Noah Hawley, who moderated the panel with Hamm and Slattery, added, "You learn, if it's an eating scene, take very few bites, and just move it around. Move it around the plate."

"We all can't be Brad Pitt," Hamm joked. "Would that we could."

It's been 10 years since Mad Men aired its finale, "Person to Person," in May 2015. The series made stars out of many of its cast members, including Hamm, Elisabeth Moss, and Christina Hendricks, all of whom were nominated for Emmys (only Hamm won, for the final season).

"I started when I was 35 years old, right through basically to 45," Hamm said, reflecting on the monumental decade that the series was on the air. "It's kind of a transitional moment in life and time, and many things. Our real lives happened, relationships started and ended, people had babies and got married and got divorced. All this crazy s--- happened in the real world, but it almost seems displaced from that in a weird way, because so much of working on the show was stepping into a time capsule."

In 2015, Mad Men network AMC released some of the show's key statistics to ring in the airing of the finale. Among them was the eye-popping stat that Mad Men's characters smoked 942 cigarettes and poured 369 drinks across seven seasons.

Like the cigs, the drinks weren't real either, and they weren't any easier to gulp down than the real things would have been. Slattery discussed on the ATX panel how the show's popular vodka martinis were replicated by suffusing water with onion.

"Pop another pearl onion in your glass of water, and then smoke 26 more fake cigarettes and it's 9:30 in the morning!" he joked.

Hamm put a sharper point on it: "Oh, the breath was lovely."