Mid-call services may be added to a communication session such as a telephone call (call session) by a wireless device on a mobile telephone network by causing the wireless device associated with the communication session to invoke a second call session directed to a vertical service code. The second call session is established on the wireless communication network and terminated on the PSTN to an application server associated with the vertical service code. The application server on the PSTN instantiates the service and matches the service associated with the vertical service code on the second call session with the first call session. The application server then applies the mid-call service associated with the vertical service code to the first call session to thus enable mid-call services to be applied to the first call session by the wireless device.