diff --git a/GObject.xs b/GObject.xs
index afccc4b..279b7a5 100644
--- a/GObject.xs
+++ b/GObject.xs
@@ -986,7 +986,7 @@ gperl_get_object_check (SV * sv,
 	if (!package)
 		croak ("INTERNAL: GType %s (%d) is not registered with GPerl!",
 		       g_type_name (gtype), gtype);
-	if (!sv || !SvROK (sv) || !sv_derived_from (sv, package))
+	if (!gperl_sv_is_defined (sv) || !SvROK (sv) || !sv_derived_from (sv, package))
 		croak ("%s is not of type %s",
 		       gperl_format_variable_for_output (sv),
 		       package);