diff --git a/django/forms/fields.py b/django/forms/fields.py
index f6d9c4db54..de14a5c8a8 100644
--- a/django/forms/fields.py
+++ b/django/forms/fields.py
@@ -399,6 +399,8 @@ class DateTimeField(Field):
             # components: date and time.
             if len(value) != 2:
                 raise ValidationError(self.error_messages['invalid'])
+            if value[0] in validators.EMPTY_VALUES and value[1] in validators.EMPTY_VALUES:
+                return None
             value = '%s %s' % tuple(value)
         for format in self.input_formats or formats.get_format('DATETIME_INPUT_FORMATS'):
             try:
diff --git a/tests/regressiontests/forms/widgets.py b/tests/regressiontests/forms/widgets.py
index 39d7d569a3..08d70c0030 100644
--- a/tests/regressiontests/forms/widgets.py
+++ b/tests/regressiontests/forms/widgets.py
@@ -1310,3 +1310,21 @@ class WidgetTests(TestCase):
         # w2 ought to be independent of w1, since MultiWidget ought
         # to make a copy of its sub-widgets when it is copied.
         self.assertEqual(w1.choices, [1,2,3])
+
+    def test_13390(self):
+        # See ticket #13390
+        class SplitDateForm(forms.Form):
+            field = forms.DateTimeField(widget=forms.SplitDateTimeWidget, required=False)
+
+        form = SplitDateForm({'field': ''})
+        self.assertTrue(form.is_valid())
+        form = SplitDateForm({'field': ['', '']})
+        self.assertTrue(form.is_valid())
+
+        class SplitDateRequiredForm(forms.Form):
+            field = forms.DateTimeField(widget=forms.SplitDateTimeWidget, required=True)
+
+        form = SplitDateRequiredForm({'field': ''})
+        self.assertFalse(form.is_valid())
+        form = SplitDateRequiredForm({'field': ['', '']})
+        self.assertFalse(form.is_valid())