I am going to take a stab at asking this… in the 90s (could also be the 80s) there was an animated film where a world need saving from an evil character that looked like Mick Jagger but it was prophesied that no one voice could defeat him. However in the end it was 2 voices (a duet) of a guy and girl (the heroes) that defeated him.
Does anyone know what film this was?
Apologies for vagueness and spoilers for anyone that may want to watch this but this is all I remember.