The focus of this article is the visual phenomenon of Chalkidian helmets decorated with artificial hair on the forehead, an image first seen on Athenian red-figure vases at the turn of the sixth century. I argue that the decision of vase-painters to add this decorative element to helmets, and thus humanize them, was influenced by the developing Athenian theatre in general, and the use of theatrical mask in particular. The interpretation is based on visual and textual evidence that suggests a conceptual relationship between the hoplite in the phalanx and the member of dramatic chorus. This interpretation has far-reaching implications. It opens new directions in considering the influence that the theatre had on Athenian vase-painters and helps to resolve the absence of explicit theatrical scenes from the corpus of vase paintings.