Tickets for the special BFI midnight event sold out faster than appearances by Martin Scorsese and Bruce Springsteen.
The star attraction on Sunday night is Jesse Armstrong, creator of Succession, who will introduce the finale to the landmark TV drama which has catapulted the unassuming screenwriter from Shropshire to the top of Hollywood's A-list.
The 450 lucky Succession obsessives will be among the first to discover which of the warring Roy clan - if any - emerges triumphant in the family saga which Armstrong, in a typically single-minded decision, has called time on after just four award-winning seasons.
Sky Atlantic viewers must set an alarm for 2am Monday to see the 90-minute conclusion.
How Armstrong, 52, the Oswestry son of a teacher-turned-crime novelist father and a mother who worked in nursery schools, was able to take such a well-observed scalpel to the power-struggles of the US media and political elite, is the subject of great debate in industry circles.
Simon Blackwell, the Emmy award-winning screenwriter who has worked with Armstrong on the hit comedies Peep Show, Veep and The Thick of It, told i: "I'm both a friend of Jesse's and a great admirer. The common thread with these shows is what happens to human beings when they are placed under an enormous amount of pressure and 24-hour scrutiny."
"That creates a lot of comedic and dramatic juice which you can apply to Westminster, Washington DC and Wall Street. You're asking the audience 'would I screw up in the same way as these people do?'. Probably, yes."
Being British outsiders helped Armstrong and his fellow writing team, including playwright Lucy Prebble, reveal truths about the US media and political elite.
"Because we're not schooled in those systems you see things that insiders maybe miss," said Blackwell, who won two Emmys for Veep, the HBO take on The Thick Of It's Whitehall farce. "We also talked to politicians on both sides of the aisle before every season to make it feel as real as possible."
This is the secret to the lacerating dialogue which has become a central feature of Succession. Blackwell, who acted as a consultant on Succession - "Jesse wanted to see if more comedy could be mined from the drama" - said: "When a character says something, you reject the standard sitcom response and ask 'what would the actual emotional response be?' You try to make it as real and as funny as possible."
Armstrong, who studied American politics and culture at university, expanded his initial script into a broader take on the swirl between media, politics and the super-rich.
He called in outside "wealth consultants" to ensure the finer details of how the "1 per cent" live were correct. Winter coats were dropped for Kendall and Roman Roy because the rich are swept directly from car to private jet, with their feet barely touching the ground.
Succession has also redefined the notion of TV success. "Its cultural impact is much bigger than its audience," Tom Standen-Jewell of media consultants Enders Analysis told i.
"You wouldn't know that Coronation Street has four times the audience of Succession from the critical buzz. But it's a big marketing tool for HBO and Sky to keep subscribers."
Zai Bennett, MD of Content at Sky, told i: "The interesting thing about Succession is that it took some time to really find its fandom. Season one didn't have the viewers that we're currently seeing throughout this final season, which is reaching over one million viewers every week".
"The show built its following gradually as people started to recommend it to their friends and colleagues. There's no doubt about it - Succession is now part of the cultural zeitgeist."
Scheduling is a factor in the series' growth too. Bennett added: "Succession works brilliantly as a weekly drop (rather than an all-episodes binge experience). It's what we call appointment viewing, where people know that Monday nights mean new Succession."
"We've seen each new episode break through across social media as soon as it's released, with quotes, jokes and memes sustaining conversation throughout the week until the next episode."
What will Armstrong do next? The Bafta-winner who lives in London with his wife is keeping his cards close to his chest.
Bennett said Sky is "lucky to have a brilliant relationship with Jesse, as well as the other creative talent on the series" but "can't reveal any future projects yet."
The boss cited Lucy Prebble and Billie Piper's celebrity satire I Hate Suzie as a series sharing some of Succession's DNA which Sky viewers have responded to.
Blackwell said: "It will be fascinating to see what Jesse does next. I would take a very big holiday because it's been a pretty relentless schedule the last few years."
In spite of pleas from viewers and cast members for more, Blackwell believes Armstrong has done the right thing to end Succession now. "Four brilliant seasons then out with everyone talking about the final episodes is the right way to go," he said.
Blackwell and other writers have also currently downed tools while the Writers Guild of America is on strike, bringing production to a halt in a dispute over payments from streaming platforms and the impact of AI on their craft.
Armstrong's path to Succession began with Channel 4's Peep Show, co-written with fellow University of Manchester student Sam Bain, which gave David Mitchell and Robert Webb their big break.
A researcher for former Labour MP Doug Henderson, Armstrong became a writer on The Thick Of It, Armando Iannucci's BBC acclaimed political satire which shares several style points- situations swiftly spiral into crisis through poor decisions - with Succession.
"Everyone praises the dialogue, which is superbly crafted with a nihilism and nastiness. That craft was honed writing comedies like Peep Show and The Thick of It for Channel 4 and the BBC," Standen-Jewell said.
"Those themes of cynicism about those in power are now widely shared in the US and UK."
As Succession showrunner, Armstrong oversees every cut an edit. He is supported by a British "writing room" team including Prebble, executive producer on the show and Tony Roche, a Thick of It alumnus who coined the word "omnishambles", as well as top director Mark Mylod.
Armstrong can be ruthless with his characters. Brian Cox admitted he was disappointed that patriarch Logan made his exit "too early" in season four.
One Armstrong project known to be still in development is Jonty, a comedy feature uniting him with Bain, starring Michael Cera. It is the story of a "coddled kid" who takes off for New York where he joins forces with an old friend to produce a terrible Broadway play.
Succession cast members including Kieran Culkin talk hopefully of a season five return in the future.
Armstrong has speculated that some characters could be revived in a spin-off and admitted he hoped that someone might "talk him out of" his decision to end the show.
There will be plenty at the BFI during Monday's early hours trying to do just that.
The final episode of Succession available on Monday, Sky Atlantic and NOW