Jay-Z did the rap on Beyoncé's "Crazy In Love" at the last minute. They had just started dating; she asked him to feature on the track the night before she had to turn in her album.
"Hot n Cold" by Katy Perry is about a real guy - an ex who would seem really interested at times but would then just disappear.
In The Band song "The Weight," Nazareth ("Went down to Nazareth") refers to a town in Pennsylvania where the Martin Guitar company was located.
Lil Wayne does an unlikely rap in a remix of the Joe Jonas song "Just In Love." The pair met at the 2008 MTV Video Music Awards.
Michael Jackson wrote the Diana Ross hit "Muscles," which he named after his pet boa constrictor.
The Ricky Martin song "She Bangs" found new life when William Hung performed it so horribly on a 2004 episode of American Idol that it went viral.
Does Angus really drink himself silly? Did their name come from a sewing machine? See if you can spot the real stories about AC/DC.
Did Rivers Cuomo grow up on a commune? Why did they name their albums after colors? See how well you know your Weezer in this Fact or Fiction.
The 10 biggest "retirement tours" that didn't take.
We've heard of artists putting their hearts into their music, but some take it literally.
For songwriters, Johnny represents the American man. He has been angry, cool, magic, a rebel and, of course, marching home.
Richie talks about producing the first two Kiss albums, recording "Brother Louie," and the newfound appreciation of his rock band, Dust.