A system for providing a talk-over functionality from an attendant to a hearing aid user comprises a hearing aid (4), a link device (5) connected to the hearing aid (4), a computer (7) with a talk-over microphone (9), and a communications link (6) linking the computer (7) to the link device (5), the hearing aid user, the hearing aid (4), and the link device (5) being positioned in a sound-proof box (1). The computer (7) is adapted for receiving signals from the microphone (9), and for executing audio processing software for processing the microphone signals for converting them into compressed, digital audio signals and transmitting these signals via the communications link (6) to the link device (5). The link device (5) is adapted for decompressing the received signals and converting them into audio signals to be served to the hearing aid (4) in real-time. The system enables an attendant or a hearing aid fitter to talk to a hearing aid user via the communications link (6). This may, for instance, be useful when the hearing aid user is acoustically isolated from the fitter during fitting of the hearing aid (4). The invention provides a system and a method for providing a talk-over functionality.