diff --git a/icu4c/source/test/intltest/numrgts.h b/icu4c/source/test/intltest/numrgts.h
index 4df2bb89923..a9f865a6afe 100644
--- a/icu4c/source/test/intltest/numrgts.h
+++ b/icu4c/source/test/intltest/numrgts.h
@@ -148,11 +148,17 @@ public:
     }
     virtual Format* clone() const 
     { return NULL; }
+
     virtual UnicodeString& format(int32_t, 
                 UnicodeString& foo, 
                 FieldPosition&) const
     { return foo.remove(); }
 
+    virtual UnicodeString& format(int64_t, 
+                UnicodeString& foo, 
+                FieldPosition&) const
+    { return foo.remove(); }
+
     virtual void applyPattern(const UnicodeString&, UParseError&, UErrorCode&){
     }
 };