#Why are anti-showering celebrities trying to make us stink?

There’s a big stink over celebrity shower habits — but experts say there might be more to this soap opera than meets the naked eye.

Jake Gyllenhaal recently became the latest in a smelly string of A-listers — from O.G. anti-deodorant duo Matthew McConaughey and Cameron Diaz to modern “wait till you see the dirt” proponents Ashton Kutcher and Mila Kunis — who are freaking out fans by admitting they embrace the funk.

“More and more I find bathing to be less necessary,” Gyllenhaal, 40, told Vanity Fair last week. His aromatic admission came virtually unprompted as the outlet had asked about his experiences in NYC as a “water town” — all tied to Gyllenhaal’s appearance in Prada’s ad for their Luna Rossa Ocean fragrance.

So, what emboldened celebs to share advice on bathing rituals — or lack thereof — with the washed masses? The annals of digital media point to a May 9, 2019 viral origin tweet by Aussie culture critic Sophie Weiner, who doesn’t think it’s “gross” to skip soap on most body parts.

Weiner’s proclamation proved contentious — with more than 10,500 retweets. Perhaps not coincidentally, Taylor Swift, 31, revealed on “Ellen” just a week later that she doesn’t — gasp — wash her legs in the shower.

One day after Swift’s confession, professional stink-raiser Yashar Ali, 41, sought to stir up controversy on Twitter by launching a racially charged bathing discourse: “What is going on with white people confessing on Twitter that they don’t wash their legs, feet, etc. in the shower and just let the water flow do the work?”

However, the dirty-or-not debate dribbled out — until Twitter user @letsassume relaunched it with a now-viral “confession” on March 23, 2021: “I only started washing my legs after the ‘white people don’t wash their legs’ discourse,” said the white woman from Baltimore. The tweeter’s admission garnered nearly 44,000 likes and 15,600 retweets.

Since then, stars such as Gyllenhaal, Kristen Bell, 41, and Dax Shepard, 46, have proudly come forward to (un)shower praise on a status pioneered by “baby wipes” legend Brad Pitt, 57. The movement has become so strong, in fact, that some stars have been forced to come forward in their own defense. “I’m not starting any trends — I shower, trust me,” Jason Momoa, 42, said Monday, adding “I’m Aquaman. I’m in the f–king water.”

Fellow Hawaiian Dwayne “The Rock” Johnson also felt the need to clarify that he bathes — and often: “I’m the opposite of a ‘not washing themselves’ celeb,” Johnson, 49, said, adding that he hits the showers up to three times per day.

Well, turns out there are certain benefits to bathing less, according to Dr. Julie Russak, a private practice dermatologist in Manhattan.

Dermies generally “don’t recommend a prolonged bath or daily showers,” Russak told The Post. Hot showers and lathering up with bath soaps “really removes and destroys the skin’s microbiome,” which plays a role in protecting the skin and is “also extremely important in overall health of the body.”

There’s still the matter of good hygiene, and “waiting for the stink” — as parents Bell and Shepard have suggested — may not be the right indicator that bath time is nigh.

“You also have to still think about all the bacteria and [toxins] that accumulate on the skin,” Russak said. “When the body sweats … it’s all a natural way of removing toxins.” Still, you don’t want to leave that sitting on top of your skin too long, encouraging pimples, folliculitis and other skin infections.

“There has to be a healthy balance,” Russak warned. Here, we ponder whether these unwashed hall of famers have found it in their sparse shower routines.

Taylor Swift

“When you shave your legs, the shaving cream is like soap, right?” Swift asked Ellen Degeneres. The two women ultimately decided at the time that, indeed, shaving does count as bathing. Then the singer was asked to clarify whether her legs are ignored when she’s not shaving.

“I kind of always shave my legs,” the 11-time Grammy winner said. Surprised by Swift’s diligent shaving regimen, Degeneres, 63, said, “You must be hairy.”

Fans were incredulous — both that Swift shaves daily and that shaving cream is equivalent to a good sudsy lather. “How is shaving cream like soap tho, lol,” one doubtful viewer dissed.

However, Dr. Russak was less than scandalized, agreeing that shaving is usually enough to do the trick. But for a better shave — and thus better clean — it’s important to exfoliate first and loosen up the dead skin cells. “If you don’t, you may become more prone to ingrown hairs,” said Russak, who is a big fan of dry-brushing her legs before a shower.

Meanwhile, Twitter is now snarking that shower habits played a role in her breakup with a certain famous ex who is rumored to have inspired the hit “Shake it Off.”

Jake Gyllenhaal

“I do believe, because Elvis Costello is wonderful — that ‘good manners and bad breath get you nowhere,’ ” said Gyllenhaal in his candid interview. “But I do also think that there’s a whole world of not bathing that is also really helpful for skin maintenance, and we naturally clean ourselves.”

Gyllenhaal’s comments splashed onto social media as fans came to both decry and defend the actor, including one steamy response: “Guys idc if Jake Gyllenhaal and Mila Kunis aren’t showering, I’ll still f–k them … in fact makes them hotter little bit.”

But are humans really self-cleaning machines? “Your body sheds dead cells, millions and millions everyday,” Russak told The Post. But modern life — from clothing to air pollution — has interrupted our body’s naturally evolved cleansing processes. In that way, showering is perhaps even more important now than when early humans lived outdoors and “were naked all the time,” she suggested.

Mila Kunis & Ashton Kutcher

It was on Dax Shepard’s podcast “Armchair Expert,” with co-host Monica Padman, that Mila Kunis, 37, came clean about how she “wasn’t that parent that bathed my newborns,” of children Wyatt Isabelle, 6, and Dimitri Portwood, 4.

Husband Ashton Kutcher, 43, then elaborated, “If you can see the dirt on them, clean them. Otherwise, there’s no point.”

Their meme-worthy comments spawned several viral responses. “When ashton kutcher and mila kunis kids walk into class,” read one tweet with nearly 93,000 likes, attached to an image of Robert Pattinson as Edward Cullen in “Twilight,” making a distinct pee-yew face while seated in a classroom.

Grime is a sure sign that a bath time is necessary, Russak agreed, adding that it’s also especially important after vigorous exercise. If you’re the sort who exercises daily, like Russak herself, a quick rinse post-workout is recommended, and using soap “only in the areas that have higher concentrations of sweat accumulation,” she said.

Kristen Bell & Dax Shepard

“I’m a big fan of waiting for the stink,” admitted “The Good Place” star Kristen Bell, 41, of her two children Lincoln, 8, and Delta, 6, on a recent episode of “The View,” appearing alongside husband Dax Shepard, 46.

In a follow-up question to Shepard’s “Armchair Expert” interview with Kutcher and Kunis, Bell added, “I don’t hate what they’re doing. I wait for the stink.”

Dr. Russak agreed: “I think we are over-bathing our children,” leading to overly sensitive skin in kids, whose dermis is already much more delicate than that of adults. She also shared that her son, who had severe eczema as a child, was allowed to shower just twice a week, and only use the gentlest soaps — to “protect his microbiome.”

Cameron Diaz

At the forefront of the pro-B.O. brigade, Cameron Diaz, now 48, told E! News in 2014 that she hasn’t used antiperspirant “for almost 20 years.”

“It’s really bad for you,” she claimed. “Just trim your armpit hair so it doesn’t hold onto the scent.”

Diaz is onto something. Sweat is our body’s “natural way of detoxifying,” said Russak. “We do need to sweat.” Deodorant — as opposed to antiperspirant, which blocks the sweat glands — is good to help control the bacteria that causes stink.

Body odor is a good indication it’s time to hit the shower. “When you smell, it’s time to take a shower,” said Dr. Russak. The bacteria that causes B.O. occur alongside the same ones that can cause infections. That said, it’s okay to skimp on soap much of the time, focusing primarily on the odor-producing areas.

Matthew McConaughey

Ever the bona fide cowboy, Matthew McConaughey, 51, has long reportedly been on the side of stink in the great deodorant debate.

“I just never wore it,” he professed in an early interview. “No cologne, no deodorant.”

He insisted the “women in [his] life” were down with the funk. “Including my mother, [they] have all said, ‘Hey, your natural smell smells, one, like a man, and, two smells like you.’ ” The number of women in McConaghey’s funky fan club who were directly related to or in a romantic relationship with the actor was not specified — but Kate Hudson sure doesn’t agree. The “Fool’s Gold” co-star allegedly begged the actor to use her natural salt rock deodorant while on set.

Julia Roberts

Julia Roberts, 53, allegedly credits her scant showering habits with concern for the environment. While the actress herself hasn’t spoken publicly about her hygiene, a 2013 tabloid reported Roberts’ bodyguard said that she “likes to save water — she’s really green.”

“She likes the smell of her natural oils,” the blabbing insider added. “She also says that she can’t wash her hair too often because it’s dry.”

Her husband, Daniel Moder, 52, is “as much of a hippie,” the guard added. “Those two are the farthest thing away from Hollywood glamour. They’re grunt all the way.”

Steve Jobs

It’s not all about movie stars: The late Apple founder Steve Jobs was known for his lifestyle quirks, one of which was revealed in the 2011 book “Steve Jobs” by Walter Isaacson. In it, the biographer claims that Jobs, as a student at Reed College in the early 1980s, held an unsubstantiated belief that a fruit-based diet would somehow eliminate his need for showers.

As a result, his stench was allegedly so bad that the young prodigy was relegated to the night shift at Atari, where he helped the company launch a video game revolution.

Jobs’ faith in fruit would come to betray him in the end after he refused treatment for pancreatic cancer on the basis that diet alone could cure his disease. Jobs passed away on Oct. 5, 2011.