Katy Perry co-wrote Iggy Azalea's hit single "Black Widow." Perry was originally going to sing on the track, but she couldn't fit it into her schedule, so Rita Ora provided the sung vocals instead.
"Toxic" was the most-searched song on Google in 2004 and helped Spears become the most-searched artist that year, a title she held from 1999-2001.
Avril Lavigne has a perfume named after her song "Black Star." It smells much better than her Sk8er Boi scent, which reeks of Axe body spray and road grime.
Neil Young wrote the CSN&Y song "Ohio" about the Kent State Shootings, when the National Guard opened fire on students at Kent State University in Ohio, killing four.
Elvis Presley' first #1 on any chart was "I Forgot To Remember To Forget." It arrived at the top of the Country tally on February 25, 1956 and stayed there for two weeks.
Amy Winehouse really did refuse "Rehab." She said she drank because she was lovesick, and "you can't go into rehab for that."
Johnny Depp, Angelina Jolie, Mila Kunis and John Malkovich are just a few of the film stars who have moonlighted in music videos.
The men of Sparks on their album Hippopotamus, and how Morrissey handled it when they suggested he lighten up.
Cain talks about the divine inspirations for "Don't Stop Believin'" and "Faithfully."
After studying in Paris with a famous composition teacher, Charles became the most successful writer of TV theme songs.
How well do you know your protest songs (including the one that went to #1)?
The Garbage drummer/songwriter produced the Nirvana album Nevermind, and Smashing Pumpkins' Gish and Siamese Dream.