Tom has found his singing voice. He chose his own improvisational microphone too, somehow innately understanding what would best serve. This is only one of a number of odd nuggets of understanding that Tom appears to have been born with, the most noticeable of which is his grasp that putting a box on your head is always funny.
There are no box-on-head moments in this clip. Just singing.
Dance To The Music from Jason B and Vimeo.