How Pharrell Williams won pole position on BBC's 'God Only Knows' all-star video

“Sorry Elton, Kylie’s inside the giant soap bubble and Paloma Faith won’t get off the celestial swing. You’ll have to make to do with CGI butterflies.”

The BBC is feeling extremely pleased with itself after unveiling an all-star Impossible Orchestra, featuring Sir Elton John, Stevie Wonder, Lorde and Pharrell Williams, performing the Beach Boys’ 1966 classic God Only Knows in a lavish promotional film, aired simultaneously across its TV and radio networks on Tuesday.

An attempt to repeat the success of a similarly stellar reworking of Lou Reed’s 'Perfect Day' 17 years ago, the “flashmob” celebrity ensemble managed to combine the diverse talents of Dave Grohl, violinist Nicola Benedetti, One Direction, the Tees Valley Youth Choir and folkie Eliza Carthy (she’s the one cooing under a platinum wig after Stevie Wonder).

The song, with its “God only know what I’d be without you” theme, is designed to “make BBC Music feel more like an all-encompassing brand for everybody,” in the words of Bob Shennan, BBC Director of Music.

Yet the project, which began two years ago, and was completed amid tight secrecy until it hijacked the airwaves and the BBC iPlayer, could have been rather different.

The original concept was to produce an orchestral version of Iron Maiden’s 'Phantom of the Opera', a seven-minute epic from the heavy metal band’s self-titled 1980 album.

“There were surprisingly few songs to choose from. We got it down to about six, including a couple of Kinks tracks, a Beatles track and a couple of David Bowie tracks,” Sam Walker, Executive Creative Director at Karmarama, the London advertising agency tasked with producing the video, told the Creative Review blog. “We were aiming for something that would appeal to as many people as possible so hopefully we chose well.”

Ethan Johns, the Kings of Leon producer, hit upon "God Only Knows", the Beach Boys’ 1966 classic and set about recording the song with an 80-piece orchestra.

The Alexander Palace Theatre in London, the location of the first ever BBC broadcast 90 years ago, was selected as the video location, the backdrop transformed through CGI animation into a fantastical, tropical setting as the song progresses.

Unlike the all-star Band Aid recordings of yore, there was no prospect of gathering the 27 illustrious musicians together for a group singalong.

The track had to be painstakingly pieced together from individually recorded lines – although A-listers with the sharpest elbows could guarantee that their contribution would play a prominent role.

“Only some artists recorded the whole song, most only recorded one line and a chorus line. Because the particular line they sang dictated where they appeared in the film visually, we had to lock their position,” Walker said.

“Once an artist had recorded a particular line that was where they had to go even if another artist came along wanting to sing that line. Once Pharrell had sung his opening line then Pharrell was always going to open the film no matter who came along after that.”

And so it came to pass that a tuxedoed Williams took pole position with the “I may not always love you” line but Jake Bugg is restricted to a token “la-la-la”.

Johns, used to working with rock’s biggest egos, admits the recording process was head-scratching. “To make so much diversity work within one piece of music was quite a challenge. I felt like I’ve taken a thousand piece puzzle and thrown it into the air.”

Will Johns’s jigsaw solution match the impact of "Perfect Day", which topped the chart when it was released as the Children In Need single, selling 1.5m copies and raising £2m?

Reed’s sombre dissection of a life in thrall to heroin relied heavily upon Bono’s contribution, with Sir Elton (again), David Bowie, Shane MacGowan, Brett Anderson from Suede and, incongruously, Boyzone providing the vocal uplift.

"God Only Knows" is a far more celebratory affair, dutifully box-ticking representatives from jazz, folk and classical alongside Radio 2-friendly big names and mandatory appearances from Jools Holland and Brian May.

With its message, that the BBC “owns” the entire musical waterfront and licence-fee payers would do well to remember that, it is the kind of propaganda film an autocratic regime sensing that its legitimacy is crumbling might produce.

However the song, which will also benefit Children in Need, is already creeping up the iTunes chart. The BBC estimates that it played to 7.3m TV viewers and 1.9m listeners on Tuesday. By Wednesday afternoon it had racked up nearly a million YouTube views.

The music critic Norman Lebrecht was not among them. “It looks like a Big Brother operation,” he wrote on his Slipped Disc blog. “Until now, only the death of a monarch or the outbreak of war was supposed to broadcast across all networks. Now, the BBC seems prepared to use that prerogative for its own propaganda and the glorification of its damply reorganised executive structure.”

But even those asking god only knows how much the BBC spent on its corporate video acknowledged one saving grace. Of Jessie J there is no sign throughout its two minute and 50 seconds duration.