diff --git a/SimG4CMS/Calo/interface/HcalTestNS.h b/SimG4CMS/Calo/interface/HcalTestNS.h
index 35c4aa0be7033..010488aa0e1f6 100644
--- a/SimG4CMS/Calo/interface/HcalTestNS.h
+++ b/SimG4CMS/Calo/interface/HcalTestNS.h
@@ -2,6 +2,7 @@
 #define SimG4CMS_HcalTestNS_h
 
 #include "Geometry/HcalCommonData/interface/HcalDDDRecConstants.h"
+#include "Geometry/HcalCommonData/interface/HcalNumberingFromDDD.h"
 
 class HcalTestNS {
 public: