Abstract: A detachable illuminating accessory for use in a mask or costume, and the associated mask or costume, in which the detachable illuminating accessory includes a top housing and a base housing, defining a cavity therebetween for one or more lighting elements and power elements providing to the lighting elements whereby the base housing includes a reversible attachment element for securing and releasing the accessory to a mask or costume, the top housing and the base housing reversibly contacting together to permit selective electrical connection between the one or more lighting elements and the one or more power elements and to provide activation of the one or more lighting elements or deactivation.