Zut alors! Could it be, that this earlier version of an Agatha Christie novel is now on assorted streaming TV channels? Taking advantage of the fact that this story will return to theaters under the care of Sir Kenneth Branagh anon?

If I was a gambling man, I’d put money on the fact that this 1978 Christie adaptation, the second starring the great Peter Ustinov, was the one that inspired Branagh and the studio then-known as 20th century Fox to revive Hercule Poirot and this old-fashioned whodunit franchise.

“Murder on the Orient Express” is the most famous Dame Agatha title, at least as far as the big screen goes. It’s a good story to stuff with an all-star cast and introduce Christie’s obnoxious, all-seeing/all-knowing sleuth and gourmand, a “proof of concept” franchise opener.

That was good enough for Ustinov and director Sidney Lumet and Paramount back in 1974, and good enough for Branagh and Fox in 2017. But the film that really sells the character, the series and the way these movies should be approached is the timelessly campy “Death on the Nile.” All these decades later, and it holds up. It’s still gloriously campy fun.

Lumet was one of the great directors his era, with “Dog Day Afternoon” and “Prince of the City” among his career highlights. But “Nile” director John Guillermin? He did “The Towering Inferno” and “King Kong” and “Skyjacked” (also “Bridge at Remagen”). Here was a man who could fill the screen with stars, give each her or his moments, and make the trains run on time.

And damned if he didn’t have a lot more giggles with Poirot & Co. than Lumet did. That’s what having Anthony Shaffer (“Sleuth,” “The Wicker Man” and Hitchcock’s “Frenzy”) as your screenwriter will do for you.

The dull opening credits — over a shot of river water — don’t hint at the acrid, hammy fun to come.

Let’s start with casting — Ustinov as Poirot (he played him many times on the big screen and on TV), David Niven as Col. Race, Bette Davis, Maggie Smith, Mia Farrow, her “Great Gatsby” co-star Lois Chiles (onetime Bond girl), a somewhat miscast George Kennedy (not awful), a seemingly more miscast Jack Warden, playing a German-Swiss doctor (he grows on you), and Olivia Hussey and Simon McCorkindale.

And none of them, not a one, has nearly as much fun as Angela Lansbury, cutting loose as a lush and best-selling romance novelist, Salome Otterbourne, floridly and drunkenly prattling on about “the calumnies of life!”

Her arrival, some 20 minutes in, is when the stodgy whodunit takes off and her co-stars let their inner ham run free. Pairing up Bette Davis, as a maybe-not-super-rich old lady, with Maggie Smith as her butch assistant and back-talking masseuse? Inspired.

“How would a little trip down the Nile suit you?

“There are two things in the world I can’t abide — It’s heat and heathens.”

Ustinov wraps his tongue around many a plummy turn of phrase. To the embittered, ditched Jacqueline (Farrow), who lost her man (McCorkindale) to her richer and prettier best friend (Chiles) — “Do not allow evil into your ‘eart. Eet weeel make a home there.”

“If love can’t live there, evil will do just as well!”

There’s all this old-fashioned national prejudice on display (the setting is the mid’30s), cracks about fetching “that Hun doctor” and the like. Poirot is the butt of many of these insults, a reminder that the Brits invented most of the world’s racial, national and ethnic slurs.

“You perfectly foul French upstart!”

“Belgian upstart, please, madame.”

“You damn froggy (French) eavesdropper!” “Belgian! Belgian eavesdropper!”

The costumes are period perfect, the setting — on a river steamer heading up the Nile, past pyramids and the like — gorgeous.

And the whodunit mystery still plays, over 40 years later. As a genre, I find those to age particularly poorly. Not here.

“Death on the Nile” is freely-adopted from the Christie novel, and I dare say Sir Ken & Crew will tinker with the story and alter it further.

For my money, the bar was low in remaking “Murder on the Orient Express” — so many versions, so few that hold up. The real test of this as a franchise, and any hopes 20th Century Studios has that new owner Disney will open the purse strings for new films, will be how much fun they wring out of “a little trip down the Nile.”

Right now, the new “Death” is slated for Oct. 23. I can hardly wait.

MPAA Rating: PG, violence and blood

Cast: Peter Ustinov, Bette Davis, David Niven, Angela Lansbury, Lois Chiles, Mia Farrow, George Kennedy, Jack Warden, Simon McCorkindale, Jon Finch and Maggie Smith.

Credits: Directed by John Guillermin, script by Anthony Shaffer. A Paramount release, now on Pluto, Amazon, etc.

Running time: 2:20