diff --git a/Objects/listobject.c b/Objects/listobject.c
index 047c6ec..ae2b549 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -2375,6 +2375,8 @@
 		PyErr_BadInternalCall();
 		return NULL;
 	}
+	if (seq->ob_type->tp_as_sequence->sq_item != list_item)
+		return PySeqIter_New(seq);
 	it = PyObject_GC_New(listiterobject, &PyListIter_Type);
 	if (it == NULL)
 		return NULL;
diff --git a/Objects/tupleobject.c b/Objects/tupleobject.c
index 282da3e..645480c 100644
--- a/Objects/tupleobject.c
+++ b/Objects/tupleobject.c
@@ -753,6 +753,8 @@
 		PyErr_BadInternalCall();
 		return NULL;
 	}
+	if (seq->ob_type->tp_as_sequence->sq_item != tupleitem)
+		return PySeqIter_New(seq);
 	it = PyObject_GC_New(tupleiterobject, &PyTupleIter_Type);
 	if (it == NULL)
 		return NULL;