It's hard to imagine a billionaire bagging groceries at a local supermarket. But believe it or not, there was a time when top-earners like Warren Buffett or Madonna weren't earning so much. Indeed, many of the world's most famous faces have had a taste of humble pie, doing things like selling plastic duckies and ringing up orders at Dunkin Donuts.

Here are the surprising odd jobs of 15 super-rich people: