As huge as Pharrell's hit song "Happy" is, it actually wasn’t supposed to feature lead vocals from the mega producer! The international smash was written and produced by Williams, but Cee-Lo Green recorded the tune first!

Pharrell recently chatted with shock jock Howard Stern earlier this week, where he revealed how the switch happened: “He did it, he did do it, but the — how do I say this diplomatically? –The powers that be at the time did not see it fit for him, and there was a much bigger agenda for him; he had bigger fish to fry, he had an album to put out,” he explained. “He sounded amazing on it. He burns my version.”

Go figure! Bet you can hear Cee-Lo singing it in your head, right? Hhmm, maybe it’ll be only a matter of time before it leaks!

Listen to Pharrell’s Howard Stern clip :