TCA: Mac's sexuality (and ripped torso) will also get the spotlight in an episode previewed for critics.

When “It’s Always Sunny In Philadelphia” returns Wednesday, September 5, we’ll see the show do something it’s only rarely done in the past: be sincere. In an episode from Season 13, previewed for critics at the Television Critics Association press tour Friday, Frank (Danny Devito) learns to be more accepting of Mac’s (Rob McElhenney) sexuality, which Mac explores with a jaw-dropping modern dance performance.

The episode, entitled “Mac Finds His Pride” is all part of the strategy for the new batch of episodes, which will feature less of Dennis (Glenn Howerton) following Howerton’s decision at the end of Season 12 to step back a bit from the long-running FX comedy.

Dennis is not completely absent from the season — “he’s in the majority of [episodes],” executive producer/star Charlie Day said — but more episodes will focus on other characters, including what’s billed as an “all-female reboot” of the classic episode “The Gang Beats Boggs,” where Dee (Kaitlin Olsen), Artemis (Artemis Pebdani), the Waitress (Mary Elizabeth Ellis), and Charlie’s mother Bonnie (Lynne Marie Stewart) will fly to Los Angeles for a women’s march… and also try to beat Wade Boggs’ drinking record.

Also a factor this season is Mac’s newly developed “Magic Mike”-esque torso, revealed initially during the season premiere and also seen in the dance number. McElhenney said his motivation to get into “Greek god”-level shape came from a fascination with scenes where guys on screen would take their shirts off.

“I don’t understand why guys who are playing teachers and engineers take their shirt off and they’re just fucking ripped,” he said. “There’s something really fun about playing into the vanity of that.”

Given “Sunny’s” history, it’s hardly a shock that McElhenney would undergo an extreme physical transformation for a joke, but what is new this season is the increased emphasis on actual character development, including Mac’s exploration of his sexuality — which has been a factor in the series since Season 12. (When asked why, McElhenney said, “It’s Season 13 — we’ve got to do something.”)

Added Day, “Our characters rarely learn… but it was nice to try something, for lack of a better term, heartfelt.”

McElhenney said when Mac originally came out, “something extraordinary happened to me”; specifically, an outpouring of positivity from LGBTQ fans of the show, which he hadn’t expected.

“They told me how moved they were and how they felt represented on an show that they loved, thousands and thousands and thousands of people,” he said.

“I didn’t think we were that kind of show and it turns out we are.”

“It’s Always Sunny in Philadelphia” Season 13 premieres September 5 at 10 p.m. on FXX.

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