diff --git a/libs/ardour/luabindings.cc b/libs/ardour/luabindings.cc
index f5f33c14e2..27a3c81cb7 100644
--- a/libs/ardour/luabindings.cc
+++ b/libs/ardour/luabindings.cc
@@ -1558,8 +1558,10 @@ LuaBindings::common (lua_State* L)
 		.addFunction ("enabled", &PluginInsert::enabled)
 		.addFunction ("strict_io_configured", &PluginInsert::strict_io_configured)
 		.addFunction ("write_immediate_event", &PluginInsert::write_immediate_event)
+		.addFunction ("thru_map", &PluginInsert::thru_map)
 		.addFunction ("input_map", (ARDOUR::ChanMapping (PluginInsert::*)(uint32_t) const)&PluginInsert::input_map)
 		.addFunction ("output_map", (ARDOUR::ChanMapping (PluginInsert::*)(uint32_t) const)&PluginInsert::output_map)
+		.addFunction ("set_thru_map", &PluginInsert::set_thru_map)
 		.addFunction ("set_input_map", &PluginInsert::set_input_map)
 		.addFunction ("set_output_map", &PluginInsert::set_output_map)
 		.addFunction ("natural_output_streams", &PluginInsert::natural_output_streams)