One of the biggest surprises of the 2018-2019 TV season came in Episode 5 of The Good Place's third season, when the bookish, perpetually flustered ethics professor Chidi Anagonye, played by William Jackson Harper, took off his shirt and revealed he was, as the kids say, serving serious body ody ody. And we're not talking adorable dad bod fitness either, but real-deal, chiseled pecs, BBQ grill abs, and sides as defined as fish gills.

Sure, Chidi had to recite all manner of highly intellectual philosophical mumbo jumbo in "Jeremy Bearimy," as he had been for the three seasons prior, but for William Jackson Harper, going topless on the thought-provoking NBC sitcom not only make him an unexpected thirst icon but it also proved to be more challenging for the actor than memorizing lines ever could.

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"I was scared sh--less," Harper told TV Guide via phone. A self-described former chubby kid who was teased in school, Harper never takes his shirt off in public and the episode made him face long-standing fears. "It was frightening," he said.

Knowing the moment was coming, 39-year-old Harper — who'd already made a sensible effort to stay in shape and eat right once he entered his 30s — was meticulous with his diet and diligent with his exercise, doing a combination of high-intensity training, cardio, and pilates. Yet he's still in disbelief over people's reaction, and not exactly ready to do it again.

William Jackson Harper, <em>The Good Place</em>William Jackson Harper, The Good Place

Until he does, Good Place fans will just have to pay attention to his acting, which, for the record, appears in just as fine shape in "Jeremy Bearimy." The episode finds Chidi and pals Eleanor (Kristen Bell), Tahani (Jameela Jamil), and Jason (Manny Jacinto) learning Janet (D'Arcy Carden) and Michael's (Ted Danson) true identities and that they've all been in the Bad Place for 300 years. Aware they cannot earn points to enter the Good Place and are doomed to return to the Bad Place, they all have unique reactions to the news, with Tahani trying philanthropy and Eleanor trying to be bad again. Chidi, for his part, embraces nihilism — a marked turn for the man who'd spin himself in circles trying to do the right thing all the time. For Chidi, learning to embrace IDGAF as a philosophy marked a personal revolution; for Harper, playing the straight man learning to embody IDGAF pushed him as a performer and may even earn him an Emmy nomination.

"It was nice to tap into that dark place," he said. "That's where I got to do something different. It was at once the easiest and the hardest to play this season." Chidi's existential crisis leads him to school his students on the three main branches of ethical philosophy — virtue ethics, consequentialism, and deontology — material that passes for conversational banter on the sneakily smart series. As the brainy center of the group, Chidi is often tasked with untangling the show's loopy timelines, as well as keeping infinite reserves of complex theoretical information at the forefront of his brain.

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For the actor, this means simply memorizing lines won't work, and digesting all this material has had irreversible effects on his own psyche. "It gets tricky," he said, but "it's important to understand [the material] because it might lead to a reaction that's more honest. Absolutely, sometimes you just gotta ask ton of questions until you get to something that makes sense. Our show is constantly throwing curveballs, and we, as the cast, get hit with those just as much as audience." Particularly since, when reading the script, he may not even have a visual cue for what's happening, Harper has to speak up and say "I don't understand" when appropriate. "Everyone's had that moment when they're like, 'What?'"

Asking for clarity pays dividends though. An admitted over-thinker who can be paralyzed by decisions just like Chidi, Harper said dealing with Chidi's rigidity regarding moral issues has made him more flexible in the best possible way. "Sometimes you have to do something distasteful that works best for the largest amount of people. I'm probably a little more open to ways of thinking about morality. [Playing Chidi] has made me more decisive." As long as he doesn't have to take his shirt off, of course.

The Good Place returns to NBC in fall. Catch previous episodes on Hulu and Netflix.