diff --git a/django/db/models/fields/__init__.py b/django/db/models/fields/__init__.py
index 720737efcf..bc6042ae59 100644
--- a/django/db/models/fields/__init__.py
+++ b/django/db/models/fields/__init__.py
@@ -475,7 +475,7 @@ class DateTimeField(DateField):
         if value is not None:
             # MySQL will throw a warning if microseconds are given, because it
             # doesn't support microseconds.
-            if settings.DATABASE_ENGINE == 'mysql':
+            if settings.DATABASE_ENGINE == 'mysql' and hasattr(value, 'microsecond'):
                 value = value.replace(microsecond=0)
             value = str(value)
         return Field.get_db_prep_save(self, value)