What to Watch Wednesday: Sir Paul on Late Show

A true living legend drops by the Late Show with David Letterman tonight: Sir Paul McCartney, formerly part of a little band called The Beatles.

This is the first appearance for McCartney on Letterman. McCartney appeared via taped interview on The Colbert Report in January.

McCartney is launching a U.S. tour on July 17 at New York's Citi Field in support of a new album - a collaboration with the band Youth that will debut under the band name The Firemen.