Billy Eichner came close to killing the gay rom-com back in September with “Bros.” Which was at least funny, even if nobody saw it. Now, here’s Jim Parsons driving a stake through the doomed gay romance.

Quite the fall. Pun intended.

“Spoiler Alert” is a weeper without tears, a dramedy with the dramatic edges rubbed off and nothing particularly funny about its “Disease of the Week” tragedy. It’s based on a memoir by a former TV Guide writer, and structured for the screen as a flaccid, endlessly voiced-over stunt in which our melodramatic memoirist remembers his childhood as the unhappiest sitcom this side of “The Conners.”

The great love of his life has died, but this is all about “me.”

And Parsons, lacking the “ba-DOOM-boom” rhythms of sitcom writing, is outclassed by “Fleabag” alumnus Ben Aldridge most of the time, even as he holds his own opposite Sally Field, who is off her game playing the mother of is character’s love interest.

It tells the story of a tepidly romantic thirteen-year love affair from the starting point of the our narrator’s other half dying. And here’s the spoiler alert about “Spoiler Alert.” It just doesn’t work.

Parsons plays Michael Ausiello, a TV Guide writer immersed in his craft — pitching “Every ‘Gilmore Girls’ character” in reverse order of obnoxiousness stories, “listicles” we call those in the trade.

Oddly, for a guy with a USC degree (we learn) he’s constantly having to have words like “chattel” and “atelier” explained to him by the hunky, “confident” ad man Kit (Aldridge) whom he meets at a gay club.

Lucky for Michael he’s “totally “Kit’s type,” a pale skinny dweeb.

They hook up and then date, and eventually Michael cannot put off inviting Kit to see his Jersey City apartment. It’s stuffed with Smurf collectibles.

“Oh God, it’s not a fetish,” is just what a guy who collects this stuff would say.

This relationship’s second biggest test will be Kit finally coming out to his parents — played by Bill Irwin and Sally Field. He’s pushing 30 and he’s never told them.

That’s another big moment of drama that isn’t in a movie that isn’t dramatic, a serious failing in a film in which we’re meant to invest in a relationship, see it tested and go “Terms of Endearment” tearful when cancer enters the picture. It doesn’t get us there.

Periodic flashbacks which can’t have worked all that well on the page take us back to Michael’s FFK (formerly fat kid) and gay childhood, sit-com scenes with a laugh track because nothing sentient would find so much as a chuckle in them.

And don’t get me started on the interminable fiasco of a third act.

Parsons was better in the sharper if dated “Boys in the Band” remake of a while back, but here he’s exposed as a classic TV “waist-up” actor, not knowing how to give us something in a close-up, but not bad at playing ungainly, seeing as how many years he had to master that via “The Big Bang Theory.” There is a romantic sparkle in his eyes you never picked up on the sitcom, and he sells his character’s attraction to the pin-up gym rat that Aldridge is typecast to play.

I’d be inclined to cut this picture some slack, as I enjoyed Parson’s run with “Big Bang,” and if anybody can make a mainstream, PG-13 gay romance palatable to the public at large, it’d have to be him.

But with every “No Longer Young Sheldon” dollop of voice-over, every moment that summons up memory’s of Cher’s greatest and most narcissistic “performance” — at Sonny Bono’s funeral — every place conflict was called for (Kit has a wandering eye, the parents potential disapproval)”Spoiler Alert” fails.

By the time the interminable finale reaches, over-reaches and gracelessly makes its exit, we’ve lost track of anything we found sweet, funny, charming or touching that came before it. Which is why I take notes, which in this case didn’t help.

Rating: PG-13 for sexual content, drug use and thematic elements

Cast: Jim Parsons, Ben Aldridge, Bill Irwin and Sally Field

Credits: Directed by Michael Showalter, scripted by David Marshall Grant and Dan Savage, based on a memoir by Michael Ausiello. A Focus Features release.

Running time: 1:52