A multimedia service providing method in a mobile communication network, the method comprising: receiving, at a message providing server, a short message from a first mobile terminal; wherein the short message indicates that the first mobile terminal requests a multimedia service from a second mobile terminal, wherein the short message comprises a transport protocol data unit, TPDU, comprising a header field including a predetermined header value in at least one of a protocol identifier, PID, field and a tele-service identifier, TID, wherein the predetermined header value indicates that the message requests the multimedia service; transmitting, by the message providing server the short message to the second mobile terminal; analyzing, by the second mobile terminal, the header field to determine whether the message requests the multimedia service; if the message requests the multimedia service, responding, by the second mobile terminal to the first mobile terminal, with a message indicating whether the multimedia service is accepted or declined; if the response message indicates accepting the multimedia service, checking, by the first mobile terminal and the second mobile terminal, whether to set a packet data protocol, PDP, session for performing the multimedia service; if the PDP session should be set, setting, by the first mobile terminal and the second mobile terminal, the PDP session for performing the multimedia service, wherein a PDP session is set between each of the terminals and a packet data serving node, PDSN, of the mobile communication network corresponding to the terminal; and registering, by each of the first mobile terminal and the second mobile terminal, using a session initiation protocol, SIP, at a corresponding call session control function, CSCF, of the mobile communication network corresponding to the terminal, characterized in that all the previous steps are performed in a state where a circuit call for voice call between the first mobile terminal and the second mobile terminal is connected. receiving, at a message providing server, a short message from a first mobile terminal; wherein the short message indicates that the first mobile terminal requests a multimedia service from a second mobile terminal, wherein the short message comprises a transport protocol data unit, TPDU, comprising a header field including a predetermined header value in at least one of a protocol identifier, PID, field and a tele-service identifier, TID, wherein the predetermined header value indicates that the message requests the multimedia service; transmitting, by the message providing server the short message to the second mobile terminal; analyzing, by the second mobile terminal, the header field to determine whether the message requests the multimedia service; if the message requests the multimedia service, responding, by the second mobile terminal to the first mobile terminal, with a message indicating whether the multimedia service is accepted or declined; if the response message indicates accepting the multimedia service, checking, by the first mobile terminal and the second mobile terminal, whether to set a packet data protocol, PDP, session for performing the multimedia service; if the PDP session should be set, setting, by the first mobile terminal and the second mobile terminal, the PDP session for performing the multimedia service, wherein a PDP session is set between each of the terminals and a packet data serving node, PDSN, of the mobile communication network corresponding to the terminal; and registering, by each of the first mobile terminal and the second mobile terminal, using a session initiation protocol, SIP, at a corresponding call session control function, CSCF, of the mobile communication network corresponding to the terminal, characterized in that all the previous steps are performed in a state where a circuit call for voice call between the first mobile terminal and the second mobile terminal is connected.