Here’s the solution for slackers who want to dress like a grown-up man, but without all the tucking, belting, buttoning and dry-cleaning: Suitsy, a onesie for the millennial age.

The get-up features a button-down shirt, suit pants and jacket — all sewn together for your convenience. All a guy’s gotta do is step in and zip up.

The Suitsy, which goes for $378, received national attention two weeks ago when its creator, Jesse Herzog, wore it on ABC’s “To Tell The Truth,” along with host Anthony Anderson.

“[There was] definitely a spike in sales and interest from when it aired nationally,” Herzog told The Post. “And I am proud to note the Suitsy is now in the personal collection of Pee Wee Herman.”

A dude enters the onesie through a concealed zipper at the front, closes the top two buttons and — voila! — he’s good to go. But he’s looking more used-car salesman than Wall Streeter.

And while the Suitsy is made of mostly cotton and spandex — making it machine washable — its quality isn’t so miraculous.

I first tried on a medium. It fit my average frame about as well as a duvet cover. The extra-large is on the Lincoln Memorial’s Christmas list. The small was better, but still baggy.

The cotton wrinkles easily and completely lacks the stiffness that is the mark of a good suit coat.

One coworker remarked that I looked “very Salvation Army.”

Walking on Madison Avenue, I felt self-conscious, as if a scarlet “S” were stamped on my chest pocket. Here I was wearing the PajamaJeans of menswear on the street that inspired Don Draper.

I walked into Bergdorf Goodman and asked some employees what they thought of my Frankensuit, fully expecting to be eviscerated.

Their answers were shocking.

“I never would’ve guessed,” one said. “It’s a great casual suit.”

“Incredible,” said another. He even showed me a $280 jacket that looked remarkably similar to the Suitsy. However, all three clerks conceded that cheaper, higher-quality three-piece suits are available at stores such as SuitSupply.

Herzog insisted that I could land a date by wearing this abomination out.

“I challenge you to wear it to a bar and not get hit on,” he said.

Challenge accepted.

A friend and I stopped by Rise in Hell’s Kitchen, where the usual attire is a tank top and shorts. Wear even a blazer and you’ll get glares that say, “Did you overshoot Per Se, sir?”

Instead, a guy walked up to us, looked right at me and suggestively said, “Hey, is that your boyfriend?”

Herzog was right. Perhaps there is a mysterious power to the Suitsy, after all. Or more likely, the bar was dark, the guy was drunk, and he was attracted to men in suits that belong at a funeral-home rummage sale.