I forgot to actually answer Gloria's question in my last posting.
 
Wollen goes on to say, "It remains an endearing irony that, in reality,
if I can so use the phrase, Debbie Reynolds's singing voice in the film
was in fact dubbed by Jean Hagen, so that what we see and hear is the
unveiling of a mystery which subverts its own appearance of
authenticity."  (p. 56, SINGIN' IN THE RAIN, London: BFI, 1992).
 
So there you have it.
 
Kelley