Psycho Diver: Soul Siren(1997)

Yuki Kano has it all: fame, wealth, the world at her feet. There's also something very wrong with her... from time to time, she's totally unable to sing (which, for a pop star, is not good). Enter Bosujima, a "psycho diver" with the capability to enter people's heads and straighten out what's wrong with them. Well, most of the time, anyway.