diff --git a/include/nuttx/audio/audio.h b/include/nuttx/audio/audio.h
index e4d9f5f4c2..6422752e00 100644
--- a/include/nuttx/audio/audio.h
+++ b/include/nuttx/audio/audio.h
@@ -332,6 +332,7 @@
 #define AUDIO_MSG_WAKEUP            9
 #define AUDIO_MSG_COMMAND          10
 #define AUDIO_MSG_SLIENCE          11
+#define AUDIO_MSG_UNDERRUN         12
 #define AUDIO_MSG_USER             64
 
 /* Audio Pipeline Buffer flags */