You're the Wizard of Oz

The story:

I lived next door to two teenage kids - a brother and sister. Every morning from 07:30 to 08:00 I heard them playing the track on their CD player before they would rehearse with a piano singing it a dozen times and then go back to the CD player to listen to the original before they ...you get the drift.
For years I thought they were singing about the Wizard of OZ until, very sophisticated, I went with friends to see the stage show in London's theatreland. I asked my friends if they knew why the song made a reference to T.W.O.Z. when there was no mention of it in the show. They thought I was winding them up and it took years for them to let me forget it. They even requested T.W.O.Z. to be played as a request on national radio!!!