I painted this double-page spread about a year ago, for
a special book on Elvis featuring artwork from comic book illustrators. I was excited to participate, and when they told me they'd like an illustration focusing on Elvis and Ali's friendship but in a "Batman and Robin action scene", I knew this would be extra fun to work on.
The finished illustration was painted in gouache and ink, and you can see below the various roughs and thumbnail drawings I did while working up the concept.