diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 3914f4dc4c..203fb1bd86 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,5 +1,24 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Deprecate on the fly monkey patch of objects in AS::Callbacks.
+    This one is probably related to before_filters:
+
+        before_filter MyFilter.new
+
+        class MyFilter
+          def filter(controller)
+          end
+        end
+
+    is now deprecated. Use:
+
+        before_filter MyFilter.new
+
+        class MyFilter
+          def before(controller)
+          end
+        end
+
 *   `ERB::Util.html_escape` encodes single quote as `#39`. Decimal form has better support in old browsers. *Kalys Osmonov*
 
 *   `ActiveSupport::Callbacks`: deprecate monkey patch of object callbacks.