diff --git a/libs/ardour/luabindings.cc b/libs/ardour/luabindings.cc
index f428213e98..c7fceb00b1 100644
--- a/libs/ardour/luabindings.cc
+++ b/libs/ardour/luabindings.cc
@@ -271,6 +271,7 @@ CLASSKEYS(ARDOUR::RouteGroup);
 CLASSKEYS(ARDOUR::ParameterDescriptor);
 CLASSKEYS(ARDOUR::PeakMeter);
 CLASSKEYS(ARDOUR::PluginInfo);
+CLASSKEYS(ARDOUR::PluginInsert);
 CLASSKEYS(ARDOUR::Plugin::PresetRecord);
 CLASSKEYS(ARDOUR::PortEngine);
 CLASSKEYS(ARDOUR::PortManager);