In 2012, art-pop livewires Sparks embarked on a tour entitled Two Hands, One Mouth.

It celebrated four colourful decades of sonic abberance and lyrical guile from LA's Ron and Russell Mael. The ingenious brothers have challenged and advanced the confines of pop music through punk, electro, opera, baroque and jazz across 22 albums and myriad surreal arias, like Angst In My Pants, The Number One Song In Heaven and, of course, This Town Ain't Big Enough For Both Of Us.

Sparks' Two Hands, One Mouth tour was the first time the Maels had performed without a backing band, and it came with its own same-titled anthem, replete with a characteristically wry and ambiguous refrain.

"Two hands, one mouth, that's all I need to satisfy you," crooned - nay, promised - tousle-mopped vocalist Russell Mael. That being so, one can barely imagine the hitherto uncharted pleasures that might be derived from ten hands and two mouths which is - at an approximate count - the anatomical make-up of FFS, Sparks' whip-smart tryst with Glasgow's Franz Ferdinand.

FFS's eponymous debut album is a dapper, orgiastic strut through art-rock, Euro-disco and vaudevillian pop, as rampantly populated by charmers, creeps and sociopaths - from come-hither serenade Things I Won't Get ("When I see you lying by my side, looking extra clean"), to cabaret-punk chorale Johnny Delusional ("Some would find me borderline attractive from afar").

As befits a pop mob with a keen eye for the spectacle, FFS's first-ever live performance was on national television, thanks to Later... With Jools Holland.

"Yeah, that was quite a baptism of fire," says Franz Ferdinand frontman Alex Kapranos. "It was crazy - they do the show live, and I was the first person to start singing, so the nerves kicked in. It felt like a pretty odd thing to do, but it also totally made sense, and it was a hell of a lot of fun. Which is pretty much how I feel about the whole project."

You can trace FFS back to 2004, when Sparks heard Franz Ferdinand's second single, Take Me Out, as keyboardist and songwriter Ron Mael - he of the clipped moustache - recalls.

"There was just something about that song," he offers. "Russell and I have always been fascinated by what you can do within the built-in restrictions of a pop song, and how you can push things forward, and Take Me Out felt like it was exploring those possibilities. That was really inspiring to us. We didn't know anything about the band, but then we happened to read an article about them where they said they had a liking of Sparks. And so a meeting was arranged. And that's how it all began.

"We don't have a lot of musician friends," Mael continues. "So it was this rare situation where we met a band and thought, you know, it's cool just to talk with them."

Sparks subsequently wrote a song, Piss Off, in a bid to woo/provoke Franz, who were duly thrilled. But their nascent collaborative plans were shelved while Kapranos and co became global pop saviours (topping the charts, bagging various BRIT Awards and the Mercury Prize) and the Mael brothers crafted more untouchable long-players, including 2009's concept pop-opera, The Seduction Of Ingmar Bergman.

Sparks and Franz Ferdinand reconvened after a chance encounter on an LA street in 2013, and this time, lightning struck. The groups spent 18 months co-writing songs across the Atlantic, before recording their FFS album in an impressive, punk-rivalling, 15 days - which goes some way to explaining the LP's sense of energy, urgency and (new) life.

"I've always felt that musicians do their best things when they're responding to other minds around them," Kapranos offers. "In the different bands I've been in over the years, there's always been these magical moments where you're doing something that's way beyond anything you'd do on your own. And these moments can be quite transient - they're really rare and they can pass quite quickly - so it's good to capture them when you can."

FFS's meeting (and melding) of minds feels anything but fleeting. It is fully-formed, strident and faintly perverse; it is all-knowing, self-goading and joyous. And it is surprising, not least to its protagonists.

"We didn't really have any intention of making an album, or doing a tour," Kapranos says. "We just kept sending songs back and forward, and it got to a point where we thought, 'Wow, this kind of feels like an album'. But neither side would broach it with the other.

"You know when you're a teenager and you start seeing someone and you're like, 'So, are we going out with each other now?' It was a bit like that," he says with a laugh. "I'm actually quite glad in a way that it didn't happen when we first met back in 2004, because I think we'd have probably just done something like our split-single with The Fire Engines, where we covered one of their songs and they covered one of ours. I think it might have been a bit more limited, whereas with the perspective this extra time has given us, we realised we could do something a lot more exciting."

Being in a six-strong band has practical benefits too, Mael suggests.

"I like the fact that you can be part of a bigger musical entity - even from the standpoint of being [less] frightened," he says. "The Two Hands, One Mouth tour was really rewarding and exciting, but that kind of thing takes years off your life, just having to be so exposed like that. Being a part of a musical organisation where you're a part of the sound, as opposed to the whole sound, is a relief in a certain sense."

So FFS is helping Ron claw back the years he shed doing Two Hands, One Mouth? "Exactly!" he laughs. "I'm getting younger every day."

If FFS heralds a new lease of life for Sparks and Franz Ferdinand, then so too does it illuminate their motley charms. Their divergent musical and lyrical voices remain distinct and yet somehow harmonious: they hit it off without ever clashing.

"I've always been a big fan of records where you've got quite different voices on them", Kapranos says. "The most extreme example, I always think, is Lee Hazlewood and Nancy Sinatra - I love the way that those two voices sound so different from each other.

"They even came up as a reference point when we were recording [burlesque murder ballad] Little Guy From The Suburbs. I said to Russell, 'You do the Nancy thing, and I'll be Lee!' And on other songs we swapped it around, so like on The Power Couple, I took the higher voice and he took the lower one. We all tried to go outside our comfort zones."

"We wanted it to be more than just this little lark by two bands," Mael adds. "This isn't a side project for anybody - this is the focus of Franz and us, for however long it lasts. We really wanted to create something where both bands would give up a little of their own sensibility in order to try and establish a new sensibility within FFS.

"Of course, both bands have such a strong identity in such different ways, and it's impossible to completely divorce yourself from your past, but we tried to do it as much as we could."

Yet whether by accident or design, FFS are also self-referential.

Mael's mention of divorce recalls a kindred track from Sparks' 2002 chamber-pop opus Lil' Beethoven, entitled I Married Myself. In it Russell lovingly warbles, "I married myself, I'm very happy together", and its self-sufficient call-to-arms is echoed on FFS's arch-prog epic Collaborations Don't Work ("I'm going to do it all by myself").

Similarly, the Japanese imagery of tech-stomp So Desu Ne recalls Sparks' 1974 masterpiece, Kimono My House, which remains an utterly unique, and vital, album in the pop canon.

"I sometimes feel Sparks haven't had the critical acclaim that they deserve," offers Kapranos. "In all the different stages of their career, they've really pushed boundaries and taken themselves to places that weren't expected. But they tend not to be loudmouths and braggarts, they tend not to shout about how wonderful and original they are - and they really are - and maybe that self-effacement makes people take them for granted."

For all that, the UK has long welcomed Sparks' kamikaze pop with open arms. Do the band feel a kinship with our small island?

"Absolutely," Mael nods. "When we first started, we had no traction in LA, and what we do has always worked better in Britain. Your bands seemed to embody the theatrics that LA groups thought was detrimental to music. In our little fantasy world, we always thought of ourselves as being a British band."

There's a track on the FFS album, The Power Couple, which sounds like a glam-punk signature song for this brand-new, almost-British band.

Review: FFS

"We must make a good impression / we must make a great impression," sing Sparks and Franz Ferdinand in unison. FFS give the distinct impression they're the sum of their parts, and much besides.

The album FFS by FFS is released by Domino Records on Monday. FFS play the Art School, Glasgow on June 16 and the Festival Theatre, Edinburgh (as part of Edinburgh International Festival) on August 24