Penguin is cock-a-hoop, and Waterstones, tweeting the latest literary news, uncovered multiple gifs on a theme I’d never encountered before: “Take my money”. Please, begged the fan army, take my money and make the book arrive faster.

They were all reacting to the news that Keanu Reeves has announced he is writing his first novel, The Book of Elsewhere, in collaboration with the award-winning British author China Miéville.

“I just nerd-flailed so hard I put my back out,” was one typical response to the announcement on Twitter, and when I say “typical”, I mean, like snowflakes (real ones, not culture warriors), no two Keanu Reeves fans are alike, and every one is beautiful.

“Ridiculously excited about this,” tweeted another fan. “Even more excited about the idea of China Miéville and Keanu Reeves being friends.” Sangeeta Waldron called it the “dream writing partnership”.

The independent bookshop Book-ish, in Crickhowell, Wales, didn’t hold back either, tweeting: “You could have knocked us over with a feather when we heard the incredible news of an upcoming novel written by the legendary Keanu Reeves and inimitable writer China Miéville.”

How to unpack this reaction? Put it this way: remember when Eleanor of Portugal married Holy Roman Emperor Frederick III, and they weren’t an obvious fit, but created an empire that held the throne continuously for the next 400 years? It’s that order of magnitude. Reeves and Miéville will wear the Weird Novel crown, conceivably forever.

For which of them, if either, does this represent a more unlikely pairing? Why the excitement? What will it be about? We can make a start on that one: it’s set in the BRZRKR comic book universe Reeves created three years ago, about an immortal warrior looking for the key to his longevity, and whose first publication became the top-selling single-issue comic since Star Wars No 1 in 2015. The rest all tugs at the threads of what, exactly, Reeves embodies for us, what we project on to his beguiling blankness. His cultural interventions arrive like precious, indecipherable message-matter from space, or the past. So intricate! There’s obviously intention here. What does it mean? Can you eat it?

The puzzle has generated its own cultural spin-offs, such as James King’s 2020 book, Be More Keanu, and the forthcoming Keanu Is Not in Love With You. They are probably as different as two books could get: the first is a cute little toilet book, patch-working together wisdom to live by from lines in his classic films. The second is a chatty investigative book about romantic scammers, many of whom, apparently, pretend to be Reeves.

Nonetheless, both books zone in on the same quality: what King calls “that famously blank expression”. Reeves’ image would be the ultimate romantic scam, having no niche, appealing equally to everyone. King elaborates on the blankness, “a face as stony as Michelangelo yet also really absorbed in the moment”. You know the way babies can look so infinitely wise? While I would never be reckless enough to call him a baby (oh my God, his fanbase), Reeves has that nullity. He is a green screen upon whom whole worlds can be projected.

And people have done: in the “manosphere” his Matrix character, Neo, spawned the red pill/blue pill trope, which has, for years, stood in for alt-right enlightenment: have you taken the right pill to slough off the “libtards” and inhabit your mastery (it’s the red one, remember)? Or there’s the “Sad Keanu” meme of 2010 – an image of Reeves sitting on a bench, eating a sandwich, looking sad, comically repurposed countless times (in my favourite, he has a cat army). Rumoured to have started on 4chan (ground zero of the manosphere), its sensibility is in fact the opposite of that, a ragtag band of the mischievous, the misfits, to whom Reeves represents the poignant melancholy of the human condition.

He never chose to be the mascot, let alone the leader, of any of this, yet the mythology is always miles ahead of him, out of his control. “Do I wish that I didn’t get my picture taken, eating a sandwich? Yeah,” he told the BBC in 2011. Yet the same year, he released the apparently referential poetry book, Ode to Happiness, in collaboration with the artist Alexandra Grant. It was scarce even then (rumours were rife that his local bookshop had more copies than Amazon); now, a second-hand hardback costs nearly $2,000 (£1,700).

That manoeuvre, of taking his apparently uncontrollable image and wrestling it in a weird direction, is repeated with the BRZRKR universe. Its high concept – tough, superhuman hero with a sensitive soul, wracked by the mystery of that contradiction and its origin – is both an echo and a reclamation of the Keanu myth itself. Whatever his motivations, they aren’t money: he is the highest paid actor of all time.

The Book of Elsewhere is a two-man tango. What’s in it for Miéville? It fits his profile, as one of the pillars of the “new weird” genre, germinated in the late 90s, to blur boundaries. I think his long-held leftwing politics may come into it, a determined Marxist rejection of the distinctions between mass v elite culture. As Alexander Cochran, of the C&W literary agency, says: “I can’t think of a better pairing than a genuine genre fan like Keanu Reeves and the literary genius China Miéville, and I can’t wait to read what they create.”