A method for providing services in a communication network, the communications network comprising a switching server, an Internet Protocol Multimedia Subsystem and one or more circuit switched access systems (40-1... 40-n), said switching server comprising an access call control entity arranged for handling one or both of circuit switched calls and services provided over circuit switched connections by means of circuit switched signalling messages to terminals (400-1... 400-n) connected to the switching server via one or more of said circuit switched access systems (40-1... 40-n), the method for further providing one or both of said circuit switched calls and services from said communication network to a terminal device connected to the switching server via said Internet Protocol Multimedia Subsystem, the method comprising: - providing said terminal device with a service providing entity for making available to a user one or both of said circuit switched calls and said services by means of said circuit switched signalling messages related to circuit switched connections; - providing a first interworking entity in said terminal device for interworking between said circuit switched signalling messages towards said access call control entity and signalling messages related to packet switched sessions towards said Internet Protocol Multimedia Subsystem, - providing a second interworking entity in said switching server between said Internet Protocol Multimedia Subsystem and said access call control entity, said second interworking entity being arranged for interworking between signalling messages related to packet switched sessions towards said Internet Protocol Multimedia Subsystem and circuit switched signalling messages towards said access call control entity, inversely to said first interworking entity, - establishing a packet switched session terminated by said first and second interworking entities, and - providing one or both of a circuit switched call and service from said access call control entity arranged for circuit switched connections to said service providing entity in said terminal device via said first and second interworking entities. - providing said terminal device with a service providing entity for making available to a user one or both of said circuit switched calls and said services by means of said circuit switched signalling messages related to circuit switched connections; - providing a first interworking entity in said terminal device for interworking between said circuit switched signalling messages towards said access call control entity and signalling messages related to packet switched sessions towards said Internet Protocol Multimedia Subsystem, - providing a second interworking entity in said switching server between said Internet Protocol Multimedia Subsystem and said access call control entity, said second interworking entity being arranged for interworking between signalling messages related to packet switched sessions towards said Internet Protocol Multimedia Subsystem and circuit switched signalling messages towards said access call control entity, inversely to said first interworking entity, - establishing a packet switched session terminated by said first and second interworking entities, and - providing one or both of a circuit switched call and service from said access call control entity arranged for circuit switched connections to said service providing entity in said terminal device via said first and second interworking entities.