diff --git a/Lib/test/test_genericclass.py b/Lib/test/test_genericclass.py
index 37a87bc6815ec2..3088a736ea168f 100644
--- a/Lib/test/test_genericclass.py
+++ b/Lib/test/test_genericclass.py
@@ -264,6 +264,13 @@ def __class_getitem__(cls, item):
                 return 'from __class_getitem__'
         self.assertEqual(C[int], 'from metaclass')
 
+    def test_class_getitem_in_runtime(self):
+        class C:
+            pass
+
+        C.__class_getitem__ = lambda cls, item: f'{cls.__name__}[{item.__name__}]'
+
+        self.assertEqual(C[int], 'C[int]')
 
 @support.cpython_only
 class CAPITest(unittest.TestCase):
diff --git a/Misc/ACKS b/Misc/ACKS
index c9fa08bd614138..86a9ac9d3505a8 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1847,3 +1847,4 @@ Doug Zongker
 Peter Åstrand
 Zheao Li
 Carsten Klein
+Batuhan Taskaya
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index e6cf4fbf30aeb6..7efcf7c26a2e92 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -3264,6 +3264,16 @@ type_setattro(PyTypeObject *type, PyObject *name, PyObject *value)
             type->tp_name);
         return -1;
     }
+    
+    if (PyUnicode_Check (name)
+        && (!strcmp (PyUnicode_AsUTF8 (name), "__init_subclass__")
+        || !strcmp (PyUnicode_AsUTF8 (name), "__class_getitem__"))
+        && PyFunction_Check (value))
+    {
+        value = PyClassMethod_New (value);
+    } 
+
+    
     if (PyUnicode_Check(name)) {
         if (PyUnicode_CheckExact(name)) {
             if (PyUnicode_READY(name) == -1)