EW.com — With all the talk surrounding Lily James’ uncanny resemblance to Pamela Anderson on Pam & Tommy — and the daily four-hour process it took for the English actress to become the blond bombshell — not enough attention has been paid to Sebastian Stan’s own intense physical transformation to play her then-husband Tommy Lee. But ever since Stan debuted on Hulu’s limited series in the premiere in nothing but a tiny thong, tatted and pierced up like the infamous Mötley Crüe drummer, it’s been clear that he’s got his own story to tell about what it took to become one-half of the ’90s tabloid royal couple.

The actor has spent years bulking up to play comic book antihero Bucky Barnes a.k.a. The Winter Soldier in many big Marvel Universe movies, but he says that losing the drastic amount of weight to play the skinny, lanky Lee was actually the most difficult physical process he’s ever experienced in his career. “I was trying to lose weight and I still felt I didn’t lose enough weight,” Stan tells EW ahead of the series finale. “And people were telling me I was crazy and going, ‘You have body dysmorphia now’ — which I always did anyway.”

Stan spent months where he stopped working out entirely to lose as much weight as possible, and then he went even further than that. “I was just running and trying to get 20,000 steps a day, and then I was fasting for 16 to 18 hours a day,” he says. “And that definitely does something, especially if you’re [driving] in traffic. But I’m proud of the whole thing.” Despite the brutal process of fasting and changing up his exercise routine to lose weight rather than build muscle, he wasn’t too worried about the negative effects on his body.

“Anybody that even has a healthy physique to some extent has body dysmorphia,” he says. “Because once you’re going into a peak, the best look possible, which by the way, I don’t care what they say, unless there’s like, magic formulas out there — which there are but some of us are not in that pocket — your body can only be at peak 100 percent for like maybe a week or something. At least, how I’ve experienced it; and I mean diet and exercise and tanning and water and lighting and everything. And then you spend the rest of the time going, ‘I’m not what I used to be.’ But it’s just all in the head.”

It took a long time for Stan to feel comfortable taking on the role of Lee, purely because of the physical aspect. “When [director] Craig Gillespie called me and said he wanted me to play this part, I thought it was a joke,” he says with a big laugh. “I don’t think I felt good about it … I don’t think I felt like I could do this until the camera test, the first time we applied the tattoos and the piercings and the costume and the hair was dyed and the whole thing.”

When Stan saw himself as Lee, alongside James as Anderson, that’s when he finally felt like he maybe could do this part justice. But that didn’t mean he stopped doubting himself throughout all of filming. “It was always difficult because I just wasn’t the same frame as him,” he says. “I had to lose so much weight, and the drums were a real pressure for me; I’d never played any instrument before and I had to learn. The whole thing felt like this just ginormous mountain to climb and there was always a little bit of an unsettling feeling about it. But I thrive well in discomfort, especially at work. It pushes you and as long as you can manage and handle it well, you can grow from it.”

By the end of production, Stan started noticing how his new/temporary rockstar look was impacting his daily life — and he definitely didn’t hate it. “People serve you coffee differently when you have tattoos, I’ve got to tell you,” he says with another laugh. “I’ve always debated a tattoo and I’ve never done it. I never got one so the little boy in me, with the tattoos, was definitely having a field day, enjoying it.”

That’s why, despite his initial hesitation and lingering feelings of discomfort, he doesn’t regret taking on a role that required him to change so much about himself. “The physical transformation is a very important part to the acting process, and whether it’s him or a fictional character, I look for those things because I get tired of myself,” Stan admits. “I do! I don’t want to do the same thing over and over again. I know my Sebastian-isms and the things that I do so I like to be challenged. And the physical aspect of it, whether it’s losing weight or gaining weight or changing hair color, it shifts perspective.”
He just wishes he had more time to prepare, lose more weight, and learn how to inhabit the character even more than how it turned out on the series. “The biggest obstacle that we had, honestly, was that we shot this so quickly,” he says. “The turnaround times were brutal and when you have to consistently maintain a certain kind of energy … in a perfect world, we would have had more time.”

All eight episodes of Pam & Tommy are now streaming on Hulu.