The “whoo-whoo” backing vocals on “Sympathy for the Devil” were added when Keith Richard‘s girlfriend, Anita Pallenberg, chimed in during a take and the Stones liked how it sounded. Pallenberg sang it on the record along with Richards, Brian Jones, Bill Wyman, Marianne Faithfull and Stones producer Jimmy Miller.
Miller: “Pallenberg was the epitome of what was happening at the time. She was very Chelsea. She’d arrive with the elite film crowd. During the recording of ‘Sympathy For The Devil’ when I started going ‘whoo, whoo’ in the control room, so did they. So I had the engineer set up a mike so they could go out in the studio and whoo, whoo for real.”