This was called the "famous person as an animal" project. I ran across this photo: link while searching for a good celebrity to morph into an animal and just felt the man had a very cheshire cat look about him.
I used some modified techniques I learned from Dave Groff, starting with a fairly tight value drawing and then adding thin washes of color. It's basically a grisaille painting. Acrylics and colored pencil on illustration board. 9" by 13.5".