A diagnostic circuit for detecting a load status of an audio amplifier, said audio amplifier comprising two output terminals for connection to at least one speaker, said diagnostic circuit comprising: - a first circuit configured to generate a first signal indicating whether a signal provided via said two output terminals comprises an audio signal; - a second circuit configured to: a) detect a first measurement signal being indicative of the output current ( I out) provided via said two output terminals, b) compare said first measurement signal with at least one threshold in order to generate a second signal indicating whether said output current ( I out) has a low current amplitude profile or a high current amplitude profile; and - a third circuit configured to generate a diagnostic signal (DIAG) as a function of said first and said second signal, wherein said diagnostic signal (DIAG) indicates an open load condition when said first signal indicates that said signal provided via said two output terminals comprises an audio signal and said second signal indicates a low current amplitude profile; characterized in that said second circuit comprises a signal evaluation circuit configured to: - elaborate said first measurement signal in order to determine whether the amplitude of said output current ( I out) is greater than a second threshold (TH2b), - determine for a given number of time instances the number of instances in which said output current ( I out) is greater than said second threshold (TH2b), and - classify said output current ( I out) as: a) a low current amplitude profile when said number of instances in which said output current ( I out) is greater than said second threshold (TH2b) is smaller than a third threshold (TH3b); and b) a high current amplitude profile when said number of instances in which said output current ( I out) is greater than said second threshold (TH2b) is greater than said third threshold (TH3b). - a first circuit configured to generate a first signal indicating whether a signal provided via said two output terminals comprises an audio signal; - a second circuit configured to: a) detect a first measurement signal being indicative of the output current ( I out) provided via said two output terminals, b) compare said first measurement signal with at least one threshold in order to generate a second signal indicating whether said output current ( I out) has a low current amplitude profile or a high current amplitude profile; and a) detect a first measurement signal being indicative of the output current ( I out) provided via said two output terminals, b) compare said first measurement signal with at least one threshold in order to generate a second signal indicating whether said output current ( I out) has a low current amplitude profile or a high current amplitude profile; and - a third circuit configured to generate a diagnostic signal (DIAG) as a function of said first and said second signal, wherein said diagnostic signal (DIAG) indicates an open load condition when said first signal indicates that said signal provided via said two output terminals comprises an audio signal and said second signal indicates a low current amplitude profile; - elaborate said first measurement signal in order to determine whether the amplitude of said output current ( I out) is greater than a second threshold (TH2b), - determine for a given number of time instances the number of instances in which said output current ( I out) is greater than said second threshold (TH2b), and - classify said output current ( I out) as: a) a low current amplitude profile when said number of instances in which said output current ( I out) is greater than said second threshold (TH2b) is smaller than a third threshold (TH3b); and b) a high current amplitude profile when said number of instances in which said output current ( I out) is greater than said second threshold (TH2b) is greater than said third threshold (TH3b). a) a low current amplitude profile when said number of instances in which said output current ( I out) is greater than said second threshold (TH2b) is smaller than a third threshold (TH3b); and b) a high current amplitude profile when said number of instances in which said output current ( I out) is greater than said second threshold (TH2b) is greater than said third threshold (TH3b).