A method of providing at least one of chat and Voice over Internet Protocol, chat/VoIP, services to a mobile User Equipment, UE, in a mobile telecommunications network, said mobile UE comprises a UE chat/VoIP client for accessing a chat/VoIP communication environment (21, 22, 23), said method comprises the steps of: - connecting a chat/VoIP service application and said UE chat/VoIP client by said mobile telecommunications network, and - connecting said chat/VoIP service application and at least one of a plurality of application server chat/VoIP clients (51, 52, 53) for accessing a plurality of chat/VoIP communication environments (21, 22, 23) operated by a plurality of chat/VoIP service providers, for providing chat/VoIP services to said UE chat/VoIP client by each accessed chat/VoIP communication environment (21, 22, 23), characterized by - acting as a chat/VoIP client, by said chat/VoIP service application, towards a connected chat/VoIP communication environment (21, 22, 23) by at least one of said plurality of application server chat/VoIP clients (51, 52, 53), said chat/VoIP communication environment (21, 22, 23) being proprietary or standardized, and - acting as a chat/VoIP communication environment, by said chat/VoIP service application, towards said UE chat/VoIP client, and wherein said chat/VoIP service application and said plurality of application server chat/VoIP clients are comprised by an application server comprised by said mobile telecommunication network, wherein said acting as a chat/VoIP client (51, 52, 53) and acting as a chat/VoIP communication environment comprise setting up and accepting chat/VoIP communication sessions (70; 71, 72, 73) providing privileged use of the mobile telecommunications network, in particular providing an agreed Quality of Service, QoS, further wherein said application server chat/VoIP clients (51, 52, 53) provide protocol conversion between a proprietary or standardized chat/VoIP communication environment (21, 22, 23) and said chat/VoIP communication environment provided by said chat/VoIP service application acting towards said UE chat/VoIP client, wherein said protocol conversion comprises coordinating and mapping of chat/VoIP services, features and functions of a chat/VoIP communication environment (21, 22, 23) to and from a UE chat/VoIP client. - connecting a chat/VoIP service application and said UE chat/VoIP client by said mobile telecommunications network, and - connecting said chat/VoIP service application and at least one of a plurality of application server chat/VoIP clients (51, 52, 53) for accessing a plurality of chat/VoIP communication environments (21, 22, 23) operated by a plurality of chat/VoIP service providers, for providing chat/VoIP services to said UE chat/VoIP client by each accessed chat/VoIP communication environment (21, 22, 23), characterized by - acting as a chat/VoIP client, by said chat/VoIP service application, towards a connected chat/VoIP communication environment (21, 22, 23) by at least one of said plurality of application server chat/VoIP clients (51, 52, 53), said chat/VoIP communication environment (21, 22, 23) being proprietary or standardized, and - acting as a chat/VoIP communication environment, by said chat/VoIP service application, towards said UE chat/VoIP client, and wherein said chat/VoIP service application and said plurality of application server chat/VoIP clients are comprised by an application server comprised by said mobile telecommunication network,