diff --git a/CHANGES b/CHANGES
index 44be3fbf9..7e1ac3aac 100644
--- a/CHANGES
+++ b/CHANGES
@@ -74,6 +74,7 @@ Bugs fixed
 * #6588: autodoc: Decorated inherited method has no documentation
 * #7469: autodoc: The change of autodoc-process-docstring for variables is
   cached unexpectedly
+* #6857: autodoc: failed to detect a classmethod on Enum class
 * #7535: sphinx-autogen: crashes when custom template uses inheritance
 * #7536: sphinx-autogen: crashes when template uses i18n feature
 * #2785: html: Bad alignment of equation links
diff --git a/sphinx/ext/autodoc/importer.py b/sphinx/ext/autodoc/importer.py
index e98b97915..432aa0c85 100644
--- a/sphinx/ext/autodoc/importer.py
+++ b/sphinx/ext/autodoc/importer.py
@@ -142,8 +142,9 @@ def get_object_members(subject: Any, objpath: List[str], attrgetter: Callable,
                 members[name] = Attribute(name, True, value)
 
         superclass = subject.__mro__[1]
-        for name, value in obj_dict.items():
+        for name in obj_dict:
             if name not in superclass.__dict__:
+                value = safe_getattr(subject, name)
                 members[name] = Attribute(name, True, value)
 
     # members in __slots__
diff --git a/tests/roots/test-ext-autodoc/target/enum.py b/tests/roots/test-ext-autodoc/target/enum.py
index d0a59c71c..c69455fb7 100644
--- a/tests/roots/test-ext-autodoc/target/enum.py
+++ b/tests/roots/test-ext-autodoc/target/enum.py
@@ -16,3 +16,8 @@ class EnumCls(enum.Enum):
     def say_hello(self):
         """a method says hello to you."""
         pass
+
+    @classmethod
+    def say_goodbye(cls):
+        """a classmethod says good-bye to you."""
+        pass
diff --git a/tests/test_autodoc.py b/tests/test_autodoc.py
index cbbdbb787..aedaa75cf 100644
--- a/tests/test_autodoc.py
+++ b/tests/test_autodoc.py
@@ -1112,8 +1112,7 @@ def test_slots(app):
 
 @pytest.mark.sphinx('html', testroot='ext-autodoc')
 def test_enum_class(app):
-    options = {"members": None,
-               "undoc-members": True}
+    options = {"members": None}
     actual = do_autodoc(app, 'class', 'target.enum.EnumCls', options)
     assert list(actual) == [
         '',
@@ -1123,6 +1122,13 @@ def test_enum_class(app):
         '   this is enum class',
         '',
         '',
+        '   .. py:method:: EnumCls.say_goodbye()',
+        '      :module: target.enum',
+        '      :classmethod:',
+        '',
+        '      a classmethod says good-bye to you.',
+        '',
+        '',
         '   .. py:method:: EnumCls.say_hello()',
         '      :module: target.enum',
         '',
@@ -1149,11 +1155,6 @@ def test_enum_class(app):
         '',
         '      doc for val3',
         '',
-        '',
-        '   .. py:attribute:: EnumCls.val4',
-        '      :module: target.enum',
-        '      :value: 34',
-        ''
     ]
 
     # checks for an attribute of EnumClass