Chances are that Jordan Berman, now pushing 30, never heard – or even heard of – a certain pop hit from 1929.

Its hook is “Those wedding bells are breaking up that old gang of mine.”

That, however, is the experience that Jordan is having through Joshua Harmon’s often hilarious, always incisive — and sometimes pathetic — comedy-drama SIGNIFICANT OTHER. It’s now in residence at the Booth Theatre on Broadway.

Not that Harmon has gone retro in making a two-act play out of a complaint that lyricists Irving Kahal and Willie Raskin conceived even before The Great Depression had started. No, Harmon has figuratively put new wine into an old bottle because Jordan’s friends aren’t the Jack and Jim mentioned in the vintage song. They’re Vanessa, Laura and Kiki – all young women who cherish this gay man as their best friend. What they have is, as Edward Kleban wrote in a wise song, “The Next Best Thing to Love” – a lyric that also noted that great friendships can also qualify as love.

What will happen when those women start finding men who just might be husbands while Jordan can’t? That’s where SIGNIFICANT OTHER gets significantly dicey. Most people would be happy for their friends, but Jordan is more concerned that he’ll lose his support system, never find a boyfriend-slash-husband and be, to cite another ‘20s reference, “single-o.” And that “o” makes Jordan feel like a zero.

Maybe it’s all for the best that he remain single, because Gideon seems obsessed with the superficialities. He talks a good ballgame about art and lofty subjects, but a pretty face and buff body (and big shoes; you know what they mean) are all he seems to value.  We glean that the current object of his affection is an utter dullard; why can’t he? Worse, when Jordan is offered a fix-up, he can only state “I don’t want to meet a guy who may be ugly.” (Kid, there’s such a thing as inner beauty, and it should be a value you value.)

Everyone, no matter of what sexual inclination or gender identity, will relate to Jordan’s first-date anxieties. We’ve all been there – and have often wished that we weren’t. We also sympathize when he flatly states that “I’m almost 29 and nobody has said he loves me.”

Alas, Jordan’s frustration eventually leads to his delivering a lengthy and inappropriate shit-fit. The immaturity he displays – disrupting what should be a happy occasion for all — instead becomes All About Him.

He’s not the only transgressor. Right from the start, we see that youth is wasted on the wasted young, thanks to Kiki’s utter drunkenness. We laugh when she says such lines as “I’ve become obsessed with myself” and blatantly lifts her dress and scratches her crotch. Then our giggles turn to a gasp of mini-horror when she mentions seeing a job applicant earlier in the day and adding “I did his screening interview.” This lush is in a position of authority?!? Later, when Vanessa tells her “You look anorexic,” she responds with a perky “Thank you!”

The thirtysomething playwright convinces us that he’s telling the truth about his millennial generation. Let’s hope, however, that all twentysomethings cherish their grandmothers as much as Jordan does. When he’s with her, he’s a stand-up caregiver, supportive listener and a grandson who’s bubbling over with genuine love.

Jordan is brought to brilliant life by Gideon Glick in a yeoman performance. He often displays a terrific smile, a mouth that moves in Claymation-fashion and eyes that are often dead – making for a solid mixture of droll wit and intense emotional pain. If there’s any justice in the theater world (and we know there’s very little), Glick will be remembered by the Tony nominators even if his show is closed by their final meeting. A shuttering could soon happen, for business has been on the wan side. That’s good news for consumers, for between TKTS and other discounts, you’ll see one of the best performances in recent years.

For that matter, all the performers are terrific. As Kiki, Sas Goldberg amusingly suggests a latter-day Chatty Cathy doll while Rebecca Naomi Jones’ Vanessa manages to convey a character with a good (and attractive) head on her shoulders. The always magnificent Lindsay Mendez adds another memorable performance to her resume as Laura, who cares more about Jordan than the other two – for all the good that gets her. Mendez has that rare ability that other actresses would maim their mothers to have – an ease in showing us that the character she’s playing is a good person.

The three actresses work extraordinarily well together as they try to keep Jordan from being the 21st century version of bachelor Bobby in COMPANY — although the Sondheim character never approaches Jordan’s level of depression.

Speaking of COMPANY, there’s an original cast member from that legendary musical on hand: Barbara Barrie, 47 years later, staunchly plays octogenarian Helene. “I feel useless,” she admits, and Barrie adds on a little brave laugh that says “And how could this have happened to me?”

Two men – Luke Smith and John Behlmann – are amazing in their ability to play six men. The latter has a six-pack that’s prominently shown – or am I being as superficial as Jordan (and another gay that Harmon’s whipped up)? Critic, heal thyself.

One liability is Mark Wendland’s terribly designed set that could confuse many theatergoers as to which room is which and what apartment belongs to whom. That there’s a netting-like obfuscation over the entire shadow-box configuration makes everything much harder to see when the actors aren’t playing at the lip of the stage.

Luckily, Trip Cullman puts them there quite often. He has a number of tiny staging touches that show a great eye – nay, great eyes — for observation. At one point, the three young women sit on a bench and chat while Jordan is across from them on a bench of his own. It happens at the point where Jordan is just beginning to realize there’s a widening gulf between them.

Harmon, who’s in his thirties, may take some heat from his own generation for suggesting that self-involved males and some not-much-better females seem to be the millennial norm. We’ve all heard that where age is concerned “70 is the new 50” and “60 is the new 40.” SIGNIFICANT OTHER makes us believe that “30 is the new 10.”