– Neil Gaiman has been too busy in recent years reworking his fantasy novels for the screen to visit his Wisconsin home, located just an hour’s drive from the Twin Cities. But when he dove into the most ambitious TV project of his career, he turned to a Minnesotan.

For “Good Omens,” the six-part miniseries dropping Friday on Amazon Prime, the writer was determined to cast Frances McDormand as the Lord Almighty, narrator of an irreverent tale about an angel and demon who team up to save the world from Armageddon. Part of the courtship was a dinner last spring with the Oscar winner and her husband, filmmaker Joel Coen, who, along with his brother Ethan, is considered Twin Cities royalty.

It didn’t take much persuading.

“Joel said, ‘Frances as the voice of God will come as no surprise to anyone in our family,’ ” Gaiman recalled at an Amazon cocktail party earlier this year.

It was a rare night off for the English writer, who has become as celebrated in Hollywood as he is in bookstores, thanks to critically acclaimed adaptations of “Stardust,” “American Gods” and “Coraline.”

But re-imagining “Good Omens,” a 1990 collaboration with fellow Englishman Terry Pratchett, is the first TV series for which Gaiman served as showrunner, meaning he supervised everything from casting to final edit.

The unprecedented commitment is tied to a promise he made before Pratchett died from Alzheimer’s in 2015.

“We had agreed that we would never do anything with ‘Good Omens’ unless it was together,” said Gaiman, who did much of his most celebrated writing in a gazebo outside Menomonie, Wis. “But then he basically wrote me and said, ‘You have to do this because I want to see it.’ And then he died, so it turned into kind of a last request. I just couldn’t be an executive producer or writer who hands in scripts and then goes away. I was determined to make something Terry would love.”

That meant maintaining much of the book’s British sensibilities. Some of the references are bound to go over Americans’ heads — including an homage to the 1946 film “A Matter of Life and Death” and a joke about former London Mayor Jeffrey Archer.

But viewers on both sides of the pond are sure to appreciate the many nods to Monty Python’s Flying Circus, most notably in the animated opening credits. They look like they might have been designed by the troupe’s Minnesota member, Terry Gilliam.

“Monty Python, and really the whole history of British comedy, were influences,” said director Douglas Mackinnon. “But ‘Good Omens’ has got its own style. The tone is that it has no tone because there was no way to manhandle it into being anything else. I think we wanted to make it look epic and glorious and wonderful and warm. I think we managed to do that.”

Casting for the stars

Gaiman didn’t limit casting to the United Kingdom, though.

When an actor had to drop out due to a family emergency, Gaiman reached out to one of the stars of NBC’s “Parks and Recreation” who also happens to own a cabin in Minnesota.

“I remember sending a text to Nick Offerman saying, ‘We’re in trouble, can you do this?’ ” Gaiman said. “He texted back saying, ‘I will buy my own plane ticket to be with you.’ Two days later, he was with us in South Africa.”

When he was thinking about who could play the by-the-book angel Gabriel, Gaiman recalled a conversation he once had with “Mad Men” star Jon Hamm.

“At some point, Jon mentioned that his favorite book in college was ‘Good Omens,’ ” Gaiman said. “I filed that away. There was a sort of joy in ransacking my address book, because I knew there were hidden ‘Good Omens’ fans all over the world.”

Other big names that showed up to play include Miranda Richardson, Michael McKean, David Morrissey and Benedict Cumberbatch, Satan to McDormand’s God.

But the most pivotal parts went to Emmy nominee Michael Sheen as Aziraphale, an angel whose greatest sin is an appetite for gourmet food, and “Doctor Who” veteran David Tennant as Crowley, a demon with a soft spot for both Aziraphale and alcohol.

For Sheen, the role offered a nice counterbalance to his part as devilish troublemaker Roland in the current season of CBS All Access’ “The Good Fight.”

“I’m probably an amalgamation of the two, but on the surface I’m more like Aziraphale, I think,” said Sheen, best known for “The Queen” and “Frost/Nixon.” “And underneath the surface I am very murky, like Roland. So somehow they’re a bit of both of me.”

In “Omens,” Aziraphale and Crowley join forces when the anti-Christ baby is placed with the wrong family, depending more on each other than their higher powers. You see their friendship develop during a montage in the first half-hour of the third episode, with the two interacting during great moments in history — including the boarding of Noah’s Ark and William Shakespeare rehearsing “Hamlet.”

“It’s the longest cold opening in the history of television, I think,” Tennant said.

One famous Brit you won’t see in this first season is Gaiman himself, despite his past appearances in “The Big Bang Theory” and “The Simpsons.”

“I’m not an actor,” said Gaiman, 58. “I’m a cheerful writer and technically, I’m now a retired showrunner who is looking forward to getting some writing done in his retirement. I’d never say never to some kind of cameo or weird thing, but it would have to be very appropriate and seductive. I would have to go, ‘Well, obviously.’ ”