1. Michael Jackson and Prince.

Prince and Jackson's rivalry has long been chinwagged. The King of Pop once sought to join forces for a song called ‘Bad’ and Prince not only rejected the offer, he mockingly re-recorded the song and sent it back to MJ. In an interview with Chris Rock, Prince said he backed out of the song because of Jackson’s opening lyric: “The first line of that song is ‘your butt is mine.’ Now, who is going to sing that to whom? Cause [he] sure ain’t singing that to me, and I sure ain’t singing it to [him].”

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2. Debbie Harry and Kanye West

Impressed by Kanye’s 2009 recording for Family Guy’s spin-off The Cleveland Show, Blondie revealed that she chatted to the rapper about working together: “He seemed so normal and easy to talk to. He didn’t seem like a jerk at all". Fast forward four years, and still no sign of a single. That being said, blondie’s new self titled album is rumoured to feature songs by Sia, Charli XCX, and possibly Kanye West.

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3. Notorious B.I.G, Jay Z, Charli Baltimore and P. Diddy

Weeks before Biggie’s death in 1997, himself, Jay Z, P. Diddy and Charli Baltimore were planning on forming a supergroup called “The Commission”. In Biggie’s track, ‘What’s Beef’, he introduces members of The Commission before laying to rest any thoughts that it was a diss song. ‘Iceberg Slim’ was for Jay Z, Biggie called himself ‘Frank Baby’ - an alias derived from the 1990 crime thriller King of New York, about a drug kingpin - and Charli Baltimore kept her original rap name, serving as the main lady of The Commission. This was also the first time that Puff Daddy’s other nickname P. Diddy was seen in a lyric, before he eventually became P. Diddy in 2001.

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4. Jimi Hendrix, Paul McCartney and Miles Davis

In 1969, Jimi Hendrix and Miles Davis had it in mind to start jamming together, along with jazz drummer Tony Williams. They wanted to include bassist icon, Paul McCartney, so Hendrix sent a telegram to The Beatles’ studio, inviting him to come and record an LP in New York. McCartney’s assistant at the time, Paul Brown, returned the request saying that McCartney was on holiday in Scotland and wouldn’t be able to fly out to the States for the impromptu jam session.

The Beatles’ star may have not received the telegram personally, but it was during this time that he was starting to move away from his band. Hendrix had split with The Experience and Davis had just started to work on Bitches Brew. One can only imagine the outcome.

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5. Les Claypool and Metallica

Primus’ Les Claypool auditioned to be Metallica’s bass player in 1986, but was turned down in favour of Jason Newsted. Claypool talked about it several times. In one account with Rolling Stone, he explained why he didn’t get the part: “I showed up with this bass that was a hunk of driftwood. I had two different coloured tennis shoes on, a bleach blonde mohawk, baggies, skater pants – I didn’t fit the bill, especially for Metallica back then.” Lead vocalist, James Hetfield said Claypool was not awarded the job because "he was too good" and that he “should do his own thing."

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6. LCD Soundsystem and Britney

LCD Soundsystem frontman, James Murphy, spilled the beans about working with Britney Spears in 2003 for her album ’In The Zone’: “It was very strange – we were both lying on the floor, head-to-head, working on lyrics in a notepad.

“She seemed eager to please, but it went nowhere. She went to dinner and just never came back.” One of the tracks, which remains untitled, surfaced on the internet last year.

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7. Pet Shop Boys and Susan Boyle

Neil Tennant of Pet Shop Boys divulged how close he came to performing with Susan Boyle at Glastonbury back in 2011. Speaking to Classic FM's Nick Ferrari, he said: "We thought she could sing the Dusty part in ‘What Have I Done To Deserve This’ , but her management felt she might not feel comfortable."

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8. David Bowie and Elvis

Country star and friend of Bowie, Dwight Yoakam, said that Elvis asked Bowie if he would produce his next record - six months before his death in 1977. The request was allegedly based on Elvis having heard Bowie’s ‘Golden Years’. Yoakam recalled it as a tragedy, saying he couldn’t even imagine a 1977 David Bowie producing Elvis: “It would have been fantastic...one of the biggest missed opportunities.”

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9. Arctic Monkeys and Girls Aloud

Alex Turner revealed in 2007 how Arctic Monkeys wanted Girls Aloud singer Sarah Harding to collaborate with them. Drummer Matt Helders said he’d already made the beat and Turner joked that they had booked studio time. “I’m finding less and less to say,” the singer went on. “I’m wilting as a frontman, right, so I’m thinking, third album, we’ll just get Sarah Harding to front this band. I’ll sing some of the old songs to keep the hardcore happy and then all the new tunes on the third album can just be her.” These jests were never made a reality in the end.

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10. Led Zeppelin and Yes

Though a seminal band in the 70s, Yes had fallen apart by the 80s, mainly due to the departures of frontman Jon Anderson and keyboardist Rick Wakeman. One day, Yes bassist Chris Squire bumped into the legendary Led Zeppelin guitarist, Jimmy Page, at a Christmas party. Squire quickly found himself consoling a grieving Page over the death of his drummer John Bonham, so he suggested that the remaining members of the two bands come together and write an album. The band went as far as getting a few demos together, but Led Zeppelin frontman Robert Plant backed out of the collaboration because he thought the music was too "complicated." Managers of the respective groups started bickering over who should become head honcho of the new band. With that, the whole project simply petered out.

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11. R.E.M and Nirvana

By 1994, Stipe, like many in Nirvana's inner circle of friends and management, had grown concerned about Cobain's dangerous drug spiral. In an attempt to try and bring Cobain back from the abyss, Stipe - the godfather of Cobain and wife Courtney Love's only child, Frances Bean - planned a collaboration with the doomed grunge singer.

"I was doing that to try to save his life. The collaboration was me calling up as an excuse to reach out to this guy. He was in a really bad place," Stipe said in an interview.

"I constructed a project to try to snap Kurt out of a frame of mind. I sent him a plane ticket and a driver, and he tacked the plane ticket to the wall in the bedroom and the driver sat outside the house for 10 hours. Kurt wouldn't come out and wouldn't answer the phone." The superstar hookup never happened and Stipe was inspired to write a musical eulogy for Cobain, ‘Let Me In’, after his death.

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12. Slash and The Stone Roses

The Guns N’ Roses guitarist offered to join The Stone Roses after John Squire left in 1996, though, the group are said to have turned him down because of his ‘leather pants’. Aziz Ibrahim, who served a brief stint as guitarist in The Stone Roses, said management were trying to piss off Squire: “They thought, ‘yeah yeah, we’ll get this big rock icon, that would really annoy John.’ Then they said something to the effect of, ‘We’re not going to work with a guy with leather pants, are we?’ So Slash wasn’t in”.

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