I need a quick reference for lecture purposes.  The story about
Jean Hagen dubbing Debbie Reynolds extradiegetically--is it really true?
Where would I find a reference to that?  I have been repeating it all my
life and now that I have to say it to 150 students I am doubting whether
or not it is true.  Did Hagen really sing the parts that Reynolds was
supposed to sing for the character Hagen portrays?
        Thank you,
 
        Gloria Monti