Earlier this month, Kanye West's released the ballad Only One, featuring the one and only Paul McCartney - or so it claimed. Upon playing, however, listeners could barely hear the former Beatle on the track. Maybe because it turned out he was simply on keyboards. In the past, musical collaborators were a tad more modest. Did you know that these lot were secretly in the background of these beloved songs?
Dusty Springfield secretly opens Elton John's The Bitch is Back. (And John Lennon plays tambourine)
We can't think of anyone less of a bitch than smokey-voiced singer Dusty Springfield, but nonetheless it was she that frequents the sassy track by Elton John, The Bitch is Back. Now, really.
During the recording, it appeared Elton had a few famous friends help him out, including John Lennon on tambourine (?!) and Dusty Springfield on backing vocals.
In fact, in her early career days, Dusty contributed secretly on a lot of songs, under the pseudonym Gladys Thong. Shocking stuff.
Upon her death, Elton returned the favour to Dusty, by singing at her funeral.
Johnny Depp plays slide guitar for Oasis
Known to fervent movie fans as the gothic hero of Tim Burton's early films - it's also no massive secret that the actor Johnny Depp is a deep lover of music. After all, he did base his most famous character Captain Jack Sparrow on The Rolling Stone's Keith Richards.
Back in the 90s, however, the up and coming star of the US could be found rubbing shoulders with Manchester band Oasis, where Depp plays slide guitar on the track 'Fade Away' - an apt title for a secret movie star cameo, don't you think?
David Bowie crops up on Arcade Fire's Reflektor
The distinct tones of David Bowie are so recognisable that we wouldn't be surprised if they could be heard all the way out into space, but perhaps some Arcade Fire fans will be slightly surprised to know the former Ziggy Stardust crops up on the band's progressive hit single Reflektor.
Lead singer Win Butler explained that Bowie forced himself upon the collaboration.
"He offered to lend us his services because he really liked the song. In fact, he basically threatened us – 'If you don't hurry up and mix this song, I might just steal it from you!'"
The Pet Shop Boys gave Robbie Williams early credibility on track 'No Regrets'
Alright, so this one was, once again, barely a closely guarded secret - but for the 90s kids now all grown up, you may be slightly taken aback to learn that the Pet Shop Boys are the cunning backing vocalists in the verses of No Regrets - a classic Robbie hit.
With no mention on the song's title, young Robbie fans had no idea what such a contemporary slice of pop they were listening to. Couldn't they have at least got Neil Tennant to poke out of a tree in the video? The pair would later collaborate more openly on disco track "She's Madonna". Phew.
Jack White sings the backing chorus on Electric Six's Danger! (High Voltage) under a sneaky pseudonym
We must admit, this piece of trivia left us in the utmost shock when we found out. Indeed, when early 2000s novelty rock track Danger! (High Voltage) was released by the camper than camp Electric Six, the multi-talented frontman of The White Stripes is the last person we'd realises was providing a second vocal on the chorus...
Hidden under the moniker "John S O' Leary", the contributor's true identity has now been given up in many interviews.
Actress Christina Ricci plays the robot voice on Beck's 'Hell Yes'.
These days, it's rather fashionable to have a famous movie star frequent your cool music video - such as this lot.
But ten years ago, Beck had already roped in a famous friend to lend a robotic hand for track Hell Yes: indie actress Christina Ricci.
How on earth did these two famous talents meet we wonder?
According to Beck, she just 'happened to be around' at the time of recording. Charming.
Mick Jagger provided uncredited backing vocals on Carly Simon's 'You're so Vain' - a song allegedly about him!
Carly Simon's anti-romantic classic is notorious for being one of the first pop records to be self-referential: "You're so vain, I bet you think this song is about you."
The person in question, was rumoured to be Rolling Stone's heartbreaker Mick Jagger. Although later confirmed not to be him, this didn't stop Jagger cheekily fuelling the fire by providing anonymous backing vocals on the hit.
So he is quite vain then.