diff --git a/gallery_dl/dt.py b/gallery_dl/dt.py
index a09e028e..74e65fe3 100644
--- a/gallery_dl/dt.py
+++ b/gallery_dl/dt.py
@@ -18,8 +18,14 @@ class NullDatetime(datetime):
     def __bool__(self):
         return False
 
+    def __str__(self):
+        return "[Invalid DateTime]"
 
-NONE = NullDatetime(101, 1, 1)
+    def __format__(self, format_spec):
+        return f"[Invalid DateTime {format_spec}]"
+
+
+NONE = NullDatetime(1, 1, 1)
 EPOCH = datetime(1970, 1, 1)
 SECOND = timedelta(0, 1)
 
diff --git a/test/test_dt.py b/test/test_dt.py
index dc00d4b4..02e3ac23 100644
--- a/test/test_dt.py
+++ b/test/test_dt.py
@@ -160,7 +160,7 @@ class TestDatetime(unittest.TestCase):
     def test_none(self):
         self.assertFalse(dt.NONE)
         self.assertIsInstance(dt.NONE, dt.datetime)
-        self.assertEqual(str(dt.NONE), "0101-01-01 00:00:00")
+        self.assertEqual(str(dt.NONE), "[Invalid DateTime]")
 
 
 if __name__ == "__main__":