diff --git a/graphene/core/classtypes/tests/test_objecttype.py b/graphene/core/classtypes/tests/test_objecttype.py
index c554dbbf..b3435179 100644
--- a/graphene/core/classtypes/tests/test_objecttype.py
+++ b/graphene/core/classtypes/tests/test_objecttype.py
@@ -54,6 +54,13 @@ def test_object_type_set_properties():
     assert h.readonly_prop == 'readonly'
     assert h.write_prop == 'custom'
 
+def test_object_type_set_private_attributes():
+    class Human(ObjectType):
+        _private_state = None
+    
+    h = Human(_private_state='custom', _other_private_state='custom')
+    assert h._private_state == 'custom'
+    assert h._other_private_state == 'custom'
 
 def test_object_type_container_invalid_kwarg():
     class Human(ObjectType):