I've also wondered about that. Anyway, according to Keno's site:
Recorded: June 5 & 6, 8 - 10, 1968. Released on Beggars Banquet in '68.
Lead Vocal: Mick Jagger
Bass: Keith Richards
Electric Guitar: Keith Richards
Maracas, other Percussion: Bill Wyman
Drums: Charlie Watts Congas: Rocky Dijon
Piano: Nicky Hopkins
"Whoo Whoo" Vocals: Keith Richards, Brian Jones, Bill Wyman, Marianne Faithfull, Anita Pallenberg & Jimmy Miller