Current techniques for behavioural specification provide the ability to describe individual methods of action, interaction and behaviour,but do not allow scripting of a complex behavioural sequence as is required for a virtual actor within the plot of a stage-play. These existing specification techniques are also designed primarily for use by computing experts, usually as a text-based language, and are therefore not easily accessible by laymen. This paper presents Petri Net Script (PNS), a new graphical language for specification of virtual actor behaviour. PNS provides a graphical interface to behavioural scripting that enables specification of actions and interactions for virtual actors that can then interact with human actors in real time. A quantitative justification as to the effectiveness of the new language is evaluated through comparison of required complexity to achieve a simple behaviour against that of a more traditional specification technique using an adaptation of McCabe's Cyclomatic Complexity.