According to Mars, he came up with the hook to the pop-rap hit last year while walking around London and slowly realizing just how broke he actually was.
"Me and [production partner] Ari Levine went out to London to work on producing and writing for an artist. We had per diems, so they gave us £250 [a few hundred dollars] each to live off of for 11 days," Mars says. "And everything there was so expensive. We were like, 'Is this the biggest mistake we've ever made? We thought we were broke in California; what are we going to do here?' So we've got no money, and I'm walking the streets and came up with, 'I wanna be a billionaire, so frickin' bad.' "
Mars might have been strapped for cash, but the 24-year-old Hawaii native was already impacting pop radio as a member of production team the Smeezingtons before the "Billionaire" refrain popped into his head. Mars' featured vocals on the song's chorus, as well as on B.o.B's Billboard Hot 100-topping "Nothin' on You," were preceded by a songwriting credit on Flo Rida's "Right Round" and production work on K'naan's "Wavin' Flag," which became the 2010 World Cup's official anthem.
Yet for Mars (real name: Peter Hernandez), it's never been about producing other people. Although he was hawking his Smeezingtons material to pay his bills, Mars' focus remained on his solo career.
On the eve of the Oct. 5 release of Mars' stylish debut album, "Doo-Wops & Hooligans," Elektra co-president John Janick thinks that the success of "Nothin' on You" and "Billionaire," as well as the steady growth of the disc's retro-romantic first single, "Just the Way You Are," have set up Mars as a multifaceted flagship artist for the recently revived label.