The foolish Kevin Costner, Francis Ford Coppola certainly caused a stir — in the worst possible way

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

I’ll give them a photo they can’t refuse, said Francis.

Respectively, they did not and they did.

While the summer box office has recently rebounded with hits like “Inside Out 2” and “Deadpool & Wolverine,” two hugely expensive vanity projects from acclaimed directors have lumbered along uncomfortably, prompting groans and shrugs on 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 degenerate into jokers over expensive boondoggles.

Both debacles cost the famed directors a whopping $100 million of their own money to make. And they certainly made a splash — in the worst way possible.

This week, the 85-year-old Coppola released a new movie trailer for his epic film “Megalopolis,” a $120 million film about the turbulent rebirth of a city that was scorned by critics when it premiered at Cannes.

The clip features quotes from reviews of his earlier work, written by Pauline Kael and John Simon, among others, to make the point that Coppola’s films, like his wine, get better with age.

The problem is that all the quotes are made up, or taken from bits about other movies. You’ll be shocked to learn that most people liked “The Godfather” when it came out.

It’s the latest humiliation for “Megalopolis,” which Coppola has been working on since 1977 and for which he sold part of his wine business to finance it.

After a rocky start in France, the indie giant even struggled to find distribution.

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

Another chaotic waste of time, Costner’s “Horizon,” has already hit theaters. And it’s a total flop.

The “Field of Dreams” actor, who was the infamous director of “Waterworld,” apparently learned nothing from that early shame.

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

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

Oops. “Chapter One” was torturous. Tumbleweeds were rolling through my head.

The unspeakably dull film debuted at Cannes to indifference and ridicule. When it hit screens in my home country, I gave it one star and said, “I couldn’t imagine spending another 540 minutes of my time on this inflated ego trip.”

But Costner has an unshakable belief in his vision, however hazy it may be.

“I did it without thinking,” he told Deadline. “It sent my accountant into a fucking frenzy. But it’s my life and I believe in the idea and the story.”

Audiences, however, did not. “Chapter One” grossed only $34 million, and the August release date for the second installment was scrapped as a result.

His last hope is that the premiere of “Chapter 2” in Venice on September 7 will be better received than the first.

Of course, you have to admire these men for putting their money where their mouth is in a stubborn pursuit of originality. Good for them.

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

Costner and Coppola, the saddest duo of the year.