The hybrid scheduling mechanism that integrates the well-known priority queueing (PQ) and generalized processor sharing (GPS) has been suggested as a highly- promising scheme for the provisioning and implementation of differentiated quality-of-service. Analytical modelling and performance evaluation of the fundamental PQ and GPS have drawn tremendous interests and received significant research efforts. However, to the best of our knowledge, there is not any analytical model reported for the hybrid mechanism. To fill this gap, this paper develops a novel analytical performance model for the hybrid PQ and GPS scheduling system subject to long-range dependent (LRD) traffic. The validity of the analytical model is demonstrated by comparing analytical results to those obtained through extensive simulation experiments.