diff --git a/skeletons/UTF8String.h b/skeletons/UTF8String.h
index ca2f0e5..1853573 100644
--- a/skeletons/UTF8String.h
+++ b/skeletons/UTF8String.h
@@ -14,6 +14,7 @@
 typedef OCTET_STRING_t UTF8String_t;	/* Implemented via OCTET STRING */
 
 extern asn_TYPE_descriptor_t asn_DEF_UTF8String;
+extern asn_TYPE_operation_t asn_OP_UTF8String;
 
 asn_struct_print_f UTF8String_print;
 asn_constr_check_f UTF8String_constraint;