It was what we call in the trade an open brief, meaning "do whatever ya want". The medley was composed of 17 or so different song segments and it was first in, first dibs from those of us interested from Ron's big phone book of animators.
As Sumo Lake had rekindled my near-dead interest in animating, I wanted to use this re-discovered joyously scribbly style and, like Sumo Lake, draw something that would be self-indulgently fun rather than having to work hard doing a caricature of a pop artist I didn't know*. I also grabbed one of the shorter segments, mindful of how much pencil mileage had to be clocked up against a tight deadline.
You can look and listen to Al's whole medley** or cut to the chase and see my full 12 seconds right here.
** [ Youtube comments would suggest audiences are more literal minded than I would have expected, or maybe just very particular about representations of livestock.]