Rescued from a corrupted hard drive by: Treehugger
The author writes:
I don't actually think he would have had the necessary sense of humour to go along with this charade, but you must admit he's one of the few who could get away with the "disguise". Voice acting himself by proxy, however...
The song title is a tribute to Jean Hagen and her marvellous voice acting in "Singing in the Rain".