In the 1970s, Sparks moved to the UK because their sensibility “was not in step at all with the US sensibility,” says the band’s Ron Mael, raising one eyebrow and offering a shy smile.

Sparks, formed in 1970 by the LA-born Mael brothers, Ron and Russell, have been one of the most idiosyncratic pop bands yet and have been name-checked as an essential influence by everyone from Morrissey, Björk and New Order to the Pet Shop Boys and Depeche Mode. They are best known for their 1974 “poperatic” No 2 hit, This Town Ain’t Big Enough for Both of Us. Their genre-defying music has variously touched — but never settled on — glam, opera, techno and chamber music but is identifiable by Ron’s witty lyrics sung by Russell’s one-of-a-kind falsetto. Rather than simply genre-hopping, they are a genre all of their own.

An article in this paper predicted a while ago that it was “not a matter of if Sparks would write a musical, but when”. And now, with their 22nd album, they have done it. The Seduction of Ingmar Bergman began life as a radio play commissioned by the Swedish national public broadcaster, Sveriges Radio. It is a lushly orchestrated Kafkaesque fantasy asking the question: “What if Bergman had moved to Hollywood?” It follows his wooing by a Hollywood studio and his surreal rescue by Greta Garbo.

The brief was simple: they had carte blanche but had to incorporate either the Swedish language or a Swedish theme. “We were pretty limited in our knowledge of Swedish culture,” Ron says. “There are, like, two cars we know of and Ikea. We did, however, know something about Ingmar Bergman. We were both really big film fans in university. At that time unless you only liked foreign film, and hated American ones, you weren’t cool.” For Ron’s final college project, with typical Sparks-ish humour, he projected Fritz Lang’s M upside-down — so that it would become W.

The Mael brothers have always been fans of cinema, so Bergman is a natural subject for them — they are like his reverse image. They are perceived as flippant and camp but have a great passion and earnestness. And Bergman? “There was a real kind of seriousness to him,” Ron says. “He actually addressed big things and was able to frame those in really pure, cinematic ways. Now those things are seen as being kind of pretentious. Everyone wants to be seen as though they don’t care about the big issues.”

Sparks’s visual presentation has always been pure European cinema. In person they come over like silent film directors — for this interview they are both dressed entirely in black. Russell’s once wild curls are now a dyed jet-black mop. Ron’s hair is scraped back, vampiric. His tiny, round, black-rimmed glasses emphasise his big eyes and the sharp angularity of his bone structure. His top lip is dusted with a John Water — style pencil moustache.

Originally Sparks’ visual trademark was Ron’s bottlebrush moustache. He had intended it as a tribute to Chaplin; it was read as a reference to Hitler. “I was more naive than I should have been as far as what the effect would be — it was meant in a silent movie kind of way. Obviously I was aware of the political aspect, but that wasn’t the thing. It became too much of a distraction, that one-inch square of hair. I thought it was best to lose it so at least we would be judged by other things.”

As well as being written as a radio play, Seduction was also conceived as a film or stage play, and with its taut libretto and lush orchestration it is hard to hear without the images unfolding in your mind. The Maels are working towards making a film of it. It wouldn’t be the first time that they had been involved in film — including a bizarre cameo as themselves in the 1977 disaster movie Rollercoaster. “We thought no one would remember it three months after its release. Now we’re tagged as the band from Rollercoaster.” Ron rolls his eyes behind his little glasses. Russell laughingly adds: “We modestly like to say it was our first co-starring role with Henry Fonda.”

More impressively, they worked with the late master of French cinema, Jacques Tati, on an unfinished film called Confusion. Over the course of a year they had many meetings with him, and their relationship with Tati feeds into their characterisation of Bergman. Like the Bergman of their libretto, Tati was fêted by Hollywood. “He showed me a letter from Paramount,” Ron recalls. “He said: ‘Oooh! They take me to Hollywood and they have a limousine for me.’ But it was kind of mocking of the whole similar situation to our fantasy Bergman thing. He could see Hollywood for what it was.”

Seduction is also informed by the six years that they spent in the late 1980s and early 1990s trying to get their own film project produced. Mai the Psychic Girl was based on a Japanese manga comic, and at one time Tim Burton was mooted as the director. Their experience fuelled the character of the Studio Head. Convinced that he can entangle Bergman in a cashorientated Faustian pact, he seeks to reassure him that his vision will not be marred by showing him Lang, F. W. Murnau and Hitchcock all lunching together in the studio canteen.

More than a decade since they last worked on Mai, Russell says that the project has recently generated some new interest and gained a “second wind. The music is all ready and we are hoping that this still might see the light of day.” Will they manage to pull this off without compromising their vision? Because, as Bergman says in Seduction, “Hollywood is not a place, it’s a sensibility. A sensibility completely at odds with my sensibility.”

The Seduction of Ingmar Bergman is broadcast on BBC 6 Music on Sunday, Nov 8, and is released on Sparks’ record label Lil’ Beethoven Records on Nov 9

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