Prince lifts intro bars?
Separated at birth? The opening bars of Stevie Wonder's "You Are the Sunshine of My Life" features vocals being handed off from a male vocal to a female and finally to Stevie himself. Prince's "1999" features the same technique, from Dez Dickerson to Lisa Coleman to Prince himself.
All the reports from the time of the recording of "1999" indicate that it was originally recorded as a group vocal, but something made Prince change his mind during the mixing of the song...
Just some food for thought.