<p>This paper examines the possibility of applying the theoretical findings of the Proteus effect, recently proposed in the field of computer game studies, to theater and film studies.</p><p>The Proteus effect is a psychological effect which is observable in the (tele-) communication environment of virtual reality, or in the play environment of a computer game when utilizing its players' avatars (visual representations of participants) in a virtual space.</p><p>The Proteus effect is that the personality traits implied by the appearances of avatars have a lasting and modifying effect on the participants' own behaviors and values.</p><p>This article focuses on the similarities between VR communication environments and theatrical performances. In either case, it can be argued that communication in a broader sense is established by participants wearing the appearances of others.</p><p>From this perspective, this paper attempts to argue the two following points. The first is confirmation that the appearances of fictional characters, which have so far attracted little theoretical attention, actually contribute to the quality of acting. Secondly, this paper recognizes an actor-like quality in the participants of cyberspace communication and in the players of computer games. By asserting the actor-like quality in these participants and game players, this thesis proposes a comprehensive perspective for discussing the role of participants of VR communication environments along with computer game players, and theatre and movie audiences.</p>