diff --git a/direct/src/interval/config_interval.cxx b/direct/src/interval/config_interval.cxx
index d486b7af11..f5033043d5 100644
--- a/direct/src/interval/config_interval.cxx
+++ b/direct/src/interval/config_interval.cxx
@@ -24,6 +24,7 @@
 #include "cMetaInterval.h"
 #include "showInterval.h"
 #include "hideInterval.h"
+#include "waitInterval.h"
 
 #include "dconfig.h"
 
@@ -65,5 +66,6 @@ init_libinterval() {
   CMetaInterval::init_type();
   ShowInterval::init_type();
   HideInterval::init_type();
+  WaitInterval::init_type();
 }