Flashback: David Gilmour and David Bowie Sing 'Comfortably Numb'

David Gilmour has performed “Comfortably Numb” at nearly every one of his solo concerts over the past three decades, and without Roger Waters onstage he’s relied on everyone from Bob Geldof to Robert Wyatt to anonymous backup singers to handle the doctor’s vocal parts. (“Just a little pinprick…”) But when his…