"It's hard to picture Paul McCartney — one of history's most celebrated songwriters, a figure of incalculable importance to modern music and pop culture — fretting over anything, least of all filling arena seats. But as NPR's Robert Siegel discovered, a few circumstances can still make the ex-Beatle sweat."

"McCartney's latest solo album, New, is out Tuesday. He recently spoke with Siegel about historical revisionists, dividing his new songs among four superstar producers, and why a little insecurity can be a successful artist's best friend. Hear the radio version at the audio link, and read more of their conversation below."

"I want to ask you about a particular song on New called "Early Days."Tell me about this one."