diff --git a/libs/ardour/ardour/filename_extensions.h b/libs/ardour/ardour/filename_extensions.h
index 6f6595f9ee..1f750dae3e 100644
--- a/libs/ardour/ardour/filename_extensions.h
+++ b/libs/ardour/ardour/filename_extensions.h
@@ -38,6 +38,7 @@ namespace ARDOUR {
 	LIBARDOUR_API extern const char* const session_archive_suffix;
 	LIBARDOUR_API extern const char* const template_archive_suffix;
 	LIBARDOUR_API extern const char* const midi_map_suffix;
+	LIBARDOUR_API extern const char* const advanced_authoring_format_suffix;
 }
 
 #endif
diff --git a/libs/ardour/filename_extensions.cc b/libs/ardour/filename_extensions.cc
index a0acd73026..505cbcc7be 100644
--- a/libs/ardour/filename_extensions.cc
+++ b/libs/ardour/filename_extensions.cc
@@ -37,5 +37,6 @@ const char* const export_format_suffix = X_(".format");
 const char* const session_archive_suffix = X_(".ardour-session-archive");
 const char* const template_archive_suffix = X_(".ardour-template-archive");
 const char* const midi_map_suffix = X_(".map");
+const char* const advanced_authoring_format_suffix = X_(".aaf");
 
 }