Ke$ha and Pitbull and harmonica | KERA News

Ke$ha and Pitbull and harmonica

Lyndsay Knecht / KERA News

It was just another workaday gig for session musician Paul Harrington. He laid down a three-and-a-half minute harmonica line, never asking where it might end up. 

"So much of what you record never gets used, so, generally, you don’t hear it again," Harrington says. 

Oh, but he did hear this one again. And again and again. If you listen to Top 40 radio with any regularity, you've heard it, too. 

Harrington's harmonica is featured on "Timber," released as the lead single on rapper Pitbull's Meltdown EP.

It's currently No. 2 on the Billboard charts.