Bruno Mars Reveals Inspiration Behind "Billionaire"

Bruno Mars: Plenty to sing about.

It's the eve of the 53rd annual Grammy Awards, and if 25-year-old Bruno Mars is nervous about his seven nominations and impending performance, you'd never know.

At his manager's house in Hollywood Hills, he chats casually by the pool with a television reporter from his native Hawaii ("After Obama," she'd later gush to me, "it's Bruno.") Then it's on to a meet-and-greet with Forbes. The premise: we'll briefly discuss the song "Billionaire" – which features...