1. A method for determining whether a speaker uttering a tested utterance belongs to a predetermined set comprising an at least one known speaker, wherein an at least one training utterance is available for each of the at least one known speaker, the method comprising the steps of: extracting an at least one first feature of each of the at least one training utterance; estimating an at least one model from the at least one first feature; extracting an at least one second feature from an at least one frame of the tested utterance; scoring the at least one second feature against an at least one of the at least one model, to obtain an at least one intermediate score; determining an at least one model score using the at least one intermediate score; selecting an at least one maximal score from the at least one model score; and the speaker is determined to belong to the predetermined set, if the at least one maximal score exceeds a threshold.