The invention provides a charging method for a communications service in a cellular communications system, especially for a prepaid communications service. A prepaid service processing node (PSPN) processes a communications service. A prepayment support node information (PI) is received from a subscriber profile database (SPD). A prepayment support node address (PA) is determined from the prepayment support node information (PI). The determined prepayment support node address (PA) is stored. A request for the communications service to be charged on a subscriber's prepayment account is detected, and a credit information request is sent to a prepayment support node (PPSC) identified by the stored prepayment support node address (PA). A credit information is received, and the requested communications service is processed according to the credit information. The invention provides a device for said charging as well.