Foolish Kevin Costner, Francis Ford Coppola certainly made a splash — in the worst way possible

If I film it, they will come, Kevin said.

I’ll make them a picture they can’t refuse, Francis said.

Respectively, they didn’t and they did.

While the summer box office has picked up recently with hits like “Inside Out 2” and “Deadpool & Wolverine,” two enormously expensive vanity projects from renowned directors have awkwardly limped along, provoking groans and shrugs across multiple continents: Kevin Costner’s “Horizon: An American Saga” and Francis Ford Coppola’s “Megalopolis.”

What were those bozos thinking? The beloved artists have willingly allowed themselves to become punchlines over pricey boondoggles.

Both debacles cost the famous directors as much as $100 million of their own money to make. And they’ve certainly made a splash — in the worst way possible.

This week, 85-year-old Coppola released a new movie trailer for his epic “Megalopolis,” a $120 million indulgence about the turbulent rebirth of a city that critics politely despised when it premiered in Cannes.

The clip includes quotes from reviews of his past work by the likes of Pauline Kael and John Simon to make the point that Coppola’s movies, like his wine, get better with age. 

Trouble is all the quotes were made up, or clipped from pieces about other movies. You’ll be shocked to learn that most people quite liked “The Godfather” when it came out.  

It’s the latest humiliation for “Megalopolis,” which Coppola has been tinkering with since 1977 and sold a piece of his wine business to fund.

After its rough bow in France, the ginormous indie even struggled to find distribution.

Its last chance at a second act is its North American premiere at the Toronto International Film Festival in two weeks. I’ll be there, pen in hand!

Another shambolic waste of time, Costner’s “Horizon,” has already hit theaters. And flopped big-time.

The “Field of Dreams” actor, who infamously directed “Waterworld,” apparently learned nothing from that early embarassment.

The 68-year-old left the massively popular “Yellowstone” and mortgaged his California estate to fund his $98 million project.

He conceived “Horizon” — which he wrote, directed and stars — as a sprawling, four-part Western; a “Game of Thrones” with wagons and scores of interconnected characters.

Whoops. “Chapter One” was torturous. Tumbleweeds rolled through my brain.

The unspeakably tedious film debuted in Cannes to indifference and derision. When it hit screens domestically, I gave it one star, saying “I could not fathom committing another 540 minutes of my time to this bloated ego trip.”

But Costner has unwavering belief in his vision, blurry though it may be.

“I did it without a thought,” he told Deadline. “It has thrown my accountant into a f—king conniption fit. But it’s my life, and I believe in the idea and the story.”

The audience, however did not. “Chapter One” grossed only $34 million, and the second entry’s August release date was scrapped as a result.

His last best hope is that the premiere of “Chapter 2” in Venice on Sept. 7 will go down better than the first. 

Of course, you have to slightly admire that these men put their money where their mouth is in dogged pursuit of originality. Good for them.

But, no matter what Coppola’s bogus, it-gets-better movie trailer asserts, history will see these “passion projects” as foolish acts of arrogance. Nothing more.

Costner and Coppola, the year’s saddest double act.