The bedrock of David Guetta's Nicki Minaj-featuring single "Hey Mama" is a sample of "Rosie," a 1940s prison recording from folk archivist Alan Lomax that songwriter Esther Dean first showed the French DJ on YouTube.
Eddie Van Halen played the guitar solo on "Beat It" as a favor to Quincy Jones, who produced the album.
The "Gunter Glieben Glauten Globen" intro in Def Leppard's "Rock Of Ages" is something their producer Mutt Lange came up with when he got tired of counting them "1, 2, 3, 4..."
Richard Harris, who played Professor Dumbledore in the first two Harry Potter movies, had a hit in 1968 with "MacArthur Park."
Al Green's "Take Me to the River" describes a baptism. Two years later, he became a reverend.
When Adele needed to cry during the filming of the video for "Hello" she played Labrinth's 2014 single "Jealous." "You could play it at my kid's birthday and I'd burst into tears," she said.
Yngwie Malmsteen and Steve Vai were two of Graham's co-writers for some '80s rock classics.
Famous songs that lent their titles - and in some cases storylines - to movies.
When a waitress wouldn't take him home, Jack wrote what would become one of the Eagles most enduring hits.
Bowie's "activist" days of 1964 led to Ziggy Stardust.
The lead singer and pianist for Procol Harum, Gary talks about finding the musical ideas to match the words.
Holly Knight talks about some of the hit songs she wrote, including "The Warrior," "Never" and "The Best," and explains some songwriting philosophy, including how to think of a bridge.