Elvis Costello Responds to Paul McCartney Hearing Costello's Voice Inside His Head

Back in September, GQ published a cover story on Paul McCartney--yes, the one with the anecdote about McCartney and John Lennon masturbating together. Elsewhere in the interview, McCartney revealed that he has an unreleased track produced by Ryan Tedder, the unfortunate pop institution behind Egypt Station dud "Fuh You," in which the ex-Beatle sings with a heavy dose of…