Elton John, Michael Jackson and Mick Jagger were all back up vocalists for artists. Photos / Bradley Garner, AP, NZPA
They're used to taking centre stage and releasing songs and albums with their names all over them.
But, back in the day, it was common practice for artists to help each other out. If they had time, they'd jump in the studio and casually record some backing vocals to add to tracks.
It might drive you crazy listening out for these secret collaborations, but you'll soon hear how important they were to the final track.
Here are a few to listen to.
Jay-Z's massive 2001 album The Blueprint cemented his place as one of the world's most famous rappers. The song Girls, Girls, Girls was a playful take on his promiscuous lifestyle - pre-Beyonce, of course.
Jay-Z kept the collaboration a secret for eight years, only revealing Jackson had contributed backing vocals to the song after the King of Pop passed away.
Although this one isn't a backing vocal, it's still worth a mention because Van Halen's guitar solo on Beat It propelled Jackson's Thriller album to cult fame.
Still the best selling album of all time with more than 65 million albums sold, Beat It was Jackson's third single after Billie Jean and The Girl is Mine.
Van Halen reportedly did the guitar solo as a favour to producer Quincy Jones; however, the rock superstar may have regretted helping out on the track.
Jackson's Thriller topped the Billboard charts for years and made sure Van Halen's 1984 album never hit number one.
Back in the day it seemed like Paul McCartney was lending his musical talent to all the biggest hits.
McCartney, aside from being a member of the Beatles, also collaborated with a number of artists.
The Beach Boys Vege-Tables, Donovan's Mellow Yellow and The Bonzo Dog Doo-Dah Band's I'm An Urban Spaceman all feature cameos from the British musician.
His most famous cameo however was with fellow Beatle John Lennon for The Rolling Stones We Love You.
For more than 40 years, fans speculated as to whom Simon's chart topper was about. When it was revealed that Rolling Stones frontman Mick Jagger had provided uncredited background vocals for the song, many observers concluded the song must be about him.
Simon always denied those rumours, telling People Magazine last year that the song was about a number of men in her life, but the second verse was strictly about Warren Beatty.
"Warren thinks the whole thing is about him!" she said, ironically matching with the song's chorus "I bet you think this song is about you."
You'd struggle to find someone who can't at least sing the Wimoweh part of The Lion Sleeps Tonight - the most famous version of which was sung by 1950s group The Tokens.
Although originally part of the doo-wop group, Sedaka went out on his own in 1957 and became a huge star.
There was a lull in his fame through the late 60s, but everything changed after meeting Elton John at a party in 1973.
John signed the singer to his American label Rocket Record Company Ltd and later lent his voice to backing vocals for the Bad Blood track. The song was a huge success, shooting up to number one on the Billboard charts where it stayed for three weeks and became his biggest commercial hit.
Grande's 2015 single is all about getting a guy's attention, but the real focal point of the song is that annoying male voice that repeatedly sings "focus on me".
Before performing at the iHeartRadio Theatre last October, Grande did a Q & A with the audience. When asked who the male vocals were on the track, the young singer revealed they were sung by "Golddigger" artist Jamie Foxx.
With more than 560 million views on Youtube, apparently not everyone finds it annoying.
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