His film, The Ballad Of Wallis Island, a quirky, wry comedy about fame and loss, also co-starring and co-written with Tim Key, was one of the UK's sleeper hits of 2025 - and described by romcom king Richard Curtis, no less, as one of the greatest British films of all time.
But set on a fictional island off the Pembrokeshire coast in Wales, it is a world away from the big-budget, A-list-filled productions it is up against at this year's BAFTAs, including One Battle After, Marty Supreme and Sinners. Basden and his co-creators will likely be brushing shoulders with Leonardo DiCaprio and Timothee Chalamet, as well as fellow nominees including Michael B Jordan, Kate Hudson, Emma Stone and Benicio Del Toro.
"In truth, we sort of feel a bit like outsiders because we made this film really on our own terms with very little in the way of budget," Basden tells Sky News. "So to be walking next to your Chalamets and your DiCaprios is obviously [going to be] completely surreal.
"I mean, yeah, we'll take it in our stride, of course, but we might end up asking for selfies, maybe."
Before this, Basden, a writer and actor, was best known for co-creating and starring in the sitcoms Plebs and Here We Go. Key has written several books and appeared in films and series, including Peep Show, Taskmaster and Greed, but is probably most recognisable as Alan Partridge collaborator Sidekick Simon.
In The Ballad Of Wallis Island, Basden plays Herb, a folk singer who once found fleeting fame alongside his former musical partner (and girlfriend) Nell, played by Carey Mulligan. Key is Charles, an eccentric two-time lottery winner and mega fan who hires the pair to play what turns out to be a reunion gig for an audience of one.
Exceedingly British, very funny, and poignant in a way that avoids cliche, it premiered at the Sundance Film Festival in the US in January last year, and won three prizes - best joint lead performance, for Key and Basden, best screenplay and best original music - at the British Independent Film Awards in November.
Now, it is up for three BAFTAs - outstanding British film, best adapted screenplay, and best supporting actress, for Mulligan.
"It's absolutely beyond our wildest expectations," Basden says of the reaction. "We've just kind of watched it grow and watched word of mouth build as it's gone on. And now to be here with three BAFTA nominations a year after it premiered… is just mind-blowing."
The film is based on their own short film, also BAFTA nominated, made in 2007, called The One and Only Herb McGwyer Plays Wallis Island - hence why it is up for adapted rather than original screenplay this time round.
Both were directed by James Griffiths, who describes the story as the "gift that keeps giving" after almost 20 years. "It feels really wonderful that we've come full circle."
Getting Mulligan on board gave the plans the momentum needed for the film to be made. Already a BAFTA winner, the actress is also a triple Oscar nominee. But perhaps most importantly (or intimidatingly), she is also married to Marcus Mumford, a real-life folk star.
"Having her there meant that not only would we become confident that the film would be good, but it also meant that people would start taking it seriously and want to come and get involved, read the script and see if there was a way that they could support it," Basden says. "I'm so happy she's been nominated, I think it's so, so deserved."
There was "never any danger" of the music being too rehearsed, he says, as the film was shot in 18 days. "We were really just having to go hell for leather. Carey and I played together a couple of times in the make-up truck, and then kind of, we just did it."
No one, not even Key, had seen them perform together beforehand. The songs were re-recorded in the studio later on, with the intention of including the more polished version in the edit, but in the end, they decided they preferred the rawness of the original takes.
"It just felt really truthful and it really felt like a band sort of finding a connection that they'd previously lost," Basden says.
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Both he and Griffiths hope the profile given by the BAFTAs will help fly the flag for other British films.
"These smaller stories, lower-budget movies that are being made here," says Basden. "Seek out the stories that we're making and feel proud that there's this creativity and brilliance at work in Britain and it doesn't all just immediately go to Hollywood.
"We've got some of the best craftspeople working in the industry here as well," adds Griffiths, highlighting in particular the remote and rugged coastline location needed for filming.
"It really is a testament to the effort and energy and enthusiasm of the crew and the craftspeople in the UK who are just happy to get their hands dirty and lug lenses up mountains and on really difficult tidal stretches of water… It certainly meant a lot of tractor rides up and down and to the coast. And poor Tom obviously spent a lot of time just wet in the cold water."
This weekend's BAFTA ceremony will hopefully be a drier and warmer experience.
"I'm just looking forward to hugging everyone that helped make the film and giving big thanks to everyone who kind of got us to this point," says Griffiths. "You know, the red carpet's kind of like a lovely finish, isn't it? But it's all the hard work that went into it and recognising all of that, that's the most important thing."
And who knows. If they do bump into Leo and Timothee, maybe they will be the ones asking for selfies
