diff --git a/libs/ardour/luabindings.cc b/libs/ardour/luabindings.cc
index 6d29e1932a..c95c0a5f2f 100644
--- a/libs/ardour/luabindings.cc
+++ b/libs/ardour/luabindings.cc
@@ -260,6 +260,12 @@ namespace LuaCairo {
 	class ImageSurface;
 	class PangoLayout;
 }
+
+namespace LuaDialog {
+	class Message;
+	class Dialog;
+}
+
 namespace Cairo {
 	class Context;
 }
@@ -268,6 +274,9 @@ CLASSKEYS(Cairo::Context);
 CLASSKEYS(LuaCairo::ImageSurface);
 CLASSKEYS(LuaCairo::PangoLayout);
 
+CLASSKEYS(LuaDialog::Message);
+CLASSKEYS(LuaDialog::Dialog);
+
 #endif // end windows special case
 
 /* Some notes on Lua bindings for libardour and friends