"Can I be your Geraldine?" read the email attached to the picture of the obsessive fan done up in leather jacket, quiff and shades, desperate to sing with Glasvegas. But this was no crazed stalker, this was a genuine collaboration offer from none other than Lady Gaga, a union that, had it ever happened, would've gone down as one of the weirdest, wildest get-togethers in rock'n'roll history, so hilarious and shocking that the internet would've run out of acronyms to portray its not-inconsiderable surprise.
It'd have been up against some stiff competition, mind. These days every chart-worthy single wears its guest appearances proudly on its sleeve – if you don't have a 'featuring Flo Rida' stuck on the end of your track title, you might as well be releasing three minutes of nocturnal flatulence called 'Not Even Worth Stealing'. But it wasn't always thus – there was a time when bands liked to help each other out without expecting a hefty cut and equal billing. Indeed, rock is smattered with examples of obscure, unusual and sometimes uncredited guest appearances. Did you know, for example, that William Shatner's 2004 cover of Pulp's 'Common People' involved contributions from Ben Folds and Joe Jackson? Or that Alanis Morissette's backing band on 'You Oughtta Know' included Flea and Dave Navarro? Or that Har Mar Superstar has appeared on every record released since 2003? Here's my favourite obscure guest slots, what are yours?
As galling as it is to admit that my favourite Beatles song was actually made better by a shadowy wife-nabbing, Enoch Powell-backing interloper, Clapton's uncredited guitar solos on 'While My Guitar Gently Weeps' are little short of sublime. In return Harrison also made an uncredited appearance on Cream's 'Badge'. And lent Clapto his wife on an open-ended basis.
Jay-Z's global bed-hopping classic is reputed to have uncredited backing vocals performed by none other than famed international lothario Michael Jackson, a rumour stoked when Jay got Jacko onstage at his Hot 97 Summer Jam gig in 2001 to wave weakly at the crowd and tell everyone he loved them.
There's still some debate as to whether it actually is Whitey – and not, as has been previously claimed, a mechanic called John S. O'Leary - squealing the chorus of his Detroit muckers Electric Six's first hit since he's never admitted it (despite pocketing a reported $60,000 for his role), but then he's still claiming Meg's his sister so one's BS detector is constantly twitching around Jack.
It seems like there was an era in the late 60s and early 70s when anyone could phone up Paul McCartney on 0800 RENT-A-BEATLE and say 'hey Paul, do you want to come and stick your face into a jockstrap full of melon juice for my new album?" and he'd be booking a cab before you've hung up. He was to be found chewing carrots and celery on The Beach Boys 'Vege-Tables' (recreated many years later on Super Furry Animals' 'Receptacle For The Respectable'), yelping and howling on Donovan's 'Mellow Yellow' and turning up on The Bonzo Dog Doo-Dah Band's 'I'm An Urban Spaceman' and with Lennon in tow on The Rolling Stones 'We Love You'. In fact, The Beatles were crazy for communal rock revelry in the 60s – the choir for 'All You Need Is Love' included Yoko, Mick Keef and Keith Moon and Linda McCartney provided backing vocals for 'Let It Be'.
Okay, so Bob doesn't actually play on Wyclef Jean's musical sabbatical announcement, but he does pop up in the video at the moment Wyclef mentions "chillin like Bob Dylan".
Not too difficult to spot this one, since not only was Damon dating Elastica singer Justine Frischmann at the time of the band recording their debut album, but his keyboard pseudonym Dan Abnormal was about as difficult to work out as if they'd credited the co-writer of 'Waking Up' as Nick Ed Itoffthestranglers.
Amazed to hear the velvety vocals of Brian Wilson all over the pounding existential angsts of Pink Floyd's miserablist epic 'The Wall'? You would have been, if they hadn't wiped his entire contribution and got session singers to reproduce it.
The harmonica on Chaka Khan's 1979 Prince-penned classic? Steive Wonder. And we are not making this up, like we did about Bob Holness on 'Baker Street', honest.