We explored the relationship between interactants' social anxiety and the interactional fidelity of virtual humans. We specifically addressed whether the contingent non-verbal feedback of virtual humans affects the association between interactants' social anxiety and their verbal self-disclosure. This subject was investigated across three experimental conditions where participants interacted with real human videos and virtual humans in computer-mediated interview interactions. The results demonstrated that socially anxious people revealed more information and greater intimate information about themselves when interacting with a virtual human when compared with real human video interaction, whereas less socially anxious people did not show this difference. We discuss the implication of this association between the interactional fidelity of virtual humans and social anxiety in a human interactant on the design of an embodied virtual agent for social skills' training and psychotherapy. Copyright © 2010 John Wiley & Sons, Ltd.