Firstly Carol Jiani did the vocals for the original version of Get On Up Do It Again, and
on Nov 2nd 2006, Carol Jiani confirmed herself on a discomusic.com forum that she did the vocals of Suzy Q's Get On Up And Do It Again and never got credited.
Then Michelle Mills (2) was the voice of Suzy Q for about a year during 1981, recording the Get On Up And Do It Again album, and whose image is used on the picture covers of the a number of 12" releases. This was confirmed by Michelle Mills in a discomusic.com forum on 30th March 2011
Between 1985 and 1987 the vocalist was Angie Vileno.