For 11 years now, Between Two Ferns has operated on a deceptively simple premise. Zach Galifianakis sits on a cheap office chair in a dingily-lit studio and passive-aggressively belittles an A-list celebrity.

Sometimes it seems like the celebrity is in on the joke, sometimes it seems like they’re not, and sometimes it seems like they were in on the joke initially but have recently started to have second thoughts. These last ones are the best.

Take the Justin Bieber interview, for example. Galifianakis greets Biber by saying how exciting it is to meet him "especially in the middle of your public meltdown". After a long, awkward pause and a handful of aborted questions, Galifianakis asks "When you're in the recording studio, do you ever ask yourself 'Hey, what if I make something that isn't shitty".

As Bieber grows more and more restless, Galifianakis asks why he wrote about 'Beliebers' in the Anne Frank museum guestbook. Then he takes off his belt, whips Bieber three times and then whoops triumphantly, all while his subject cowers wordlessly in his chair.

And for 11 years, Between Two Ferns has been content to be small scale and web only. Every now and again a new episode will pop up on FunnyorDie, you’ll have the time of your life for a handful of minutes and then you’ll move on. It hasn’t required much in the way of investment from us.

But that changes now, because this week a full-length Between Two Ferns movie will debut on Netflix: one hour and 22 minutes of traditional Between Two Ferns interviews, interspersed with explosions and helicopters and what looks very much like a giant fibreglass swan.

It’s a radical departure for the show, and that’s a risk. Because why would anyone tinker with a format as perfect as Between Two Ferns? The series predates The Hangover – and Galifianakis’ rise to international fame – by a year, and it shows. This is an older Galifianakis persona, one that feels like a remnant from another age. He isn’t simply playing a rube or a weirdo here, like he did in the Hangover series or Due Date.

He’s a raw nerve. He’s surly and dispeptic, consumed by bitterness but also absurdly sensitive to the slightest criticism. He’s dismissive as a defence mechanism. The show’s theme tune is a muzak version of the Taxi Driver theme for a reason. All he wants is to be accepted by those he admires, but he isn’t, so instead he goes on the attack. It’s a much, much more complex character than it needs to be, and this is the secret success of the show.

And it’s massively influential too. You can see elements of Between Two Ferns in the Comedy Bang Bang TV show (created by Between Two Ferns director Scott Aukerman) and the squalid nihilism of my beloved Eric Andre Show. To watch John C Reilly’s Check It Out with Steve Brule is to see the precise intersection of Tim and Eric’s community theatre ethos and Between Two Ferns.

In fact, it’s Tim and Eric that has me most worried about Between Two Ferns: The Movie. After all, they made their mark with their intensely weird, short-form Awesome Show, but when it came to transferring to the big screen – as they did with 2012’s Tim and Eric’s Billion Dollar Movie – the result was a heavily diluted product.

They just couldn’t sustain their weirdness for that long, and once it had added in all the boring stuff that Hollywood movies require, like plot and character development, it was a shadow of what it could have been. As a result, it was a critical and commercial failure.

But if the Between Two Ferns movie can capture the spirit of the series, and balance it finely with its new form, we might have something really special. Because the best moments in Between Two Ferns come when things appear to deviate from the script. 

The best interviews of all time have been the ones where the interviewer and interviewee haven't got along. Michael Parkinson and Meg Ryan. Clive Anderson and the Bee Gees. David Letterman and Crispin Glover. The Constance Wu interview in the latest New Yorker.

So many interviews are bland, nothingy, frictionless promotional tools that you never get the chance to see the real person behind the persona. When an interview goes wrong, you finally get a glimpse of the engine that drives a star. Between Two Ferns is partially scripted, and the interviewees usually know what they're getting themselves into, but it scratches that same itch. It's a moment of rawness amid a fawning industry.

For the most part, an early Bradley Cooper episode is exactly what you’d expect it to be; with two friends and co-stars putting on a faux-combative display. It doesn’t really kick into gear until Cooper off-handedly laughs at a weak joke. Galifianakis mimics the laugh, but it’s grizzled and cancerous and truly dark, like the last wheeze of a dying rhino. From that point onwards, the episode takes on an air of real menace, and it’s fascinating to watch. 

Same with the Sean Penn episode, hosted by Zach Galifianakis’ country boy twin Seth. Throughout the entire interview, Penn strikes a tone of exhausted tolerance. But then, midway through, Seth pushes just a little too far and Penn reacts by threatening violence. We may never know how much of this was real and how much of it was an act, but in a recent interview with David Letterman, Galifianakis revealed that he was legitimately scared of being beaten up.

There are so many classic episodes to enjoy. Steve Carell, who comes out swinging with fat jokes (“I hear the camera adds ten pounds – you must have eaten five cameras"). Conan O’Brien, who is far too eager to please. Bruce Willis, who sits in silence before unveiling a staggeringly dirty story. Brad Pitt, who does something unsightly with a piece of chewing gum. “Tell me what it was like the first time that you laid eyes on Angelina," Galifianakis asks Jennifer Aniston's former lover. "Was it like one of those classical love stories like when Ross first saw Rachel. You know, that show ‘Friends,’ have you seen that?” He then plays the Friends theme tune as Pitt squirms.

Which isn’t to say that every episode has been a hit. For a brief moment, Between Two Ferns became just another stop on the campaign trail for politicians eager to reach an audience not traditionally served by debates and newspapers, and this is when it wobbled the hardest. Barack Obama just about held his own, hitting the correct tone and burying his message of healthcare reform under a thick layer of fat jokes. But Hillary Clinton’s episode was representative of the show at its worst; flat and over-rehearsed, and not nearly combative enough.

Between Two Ferns: The Movie has an impressive roster of celebrity participants. Jon Hamm, Benedict Cumberbatch, Brie Larson, Keanu Reeves, Matthew McConaughey, Tessa Thompson and David Letterman are all set to take part. They won’t all be hits, but if the net result is even half as good as the series, then this has the potential to be really special.