diff --git a/actionpack/lib/action_controller/metal/instrumentation.rb b/actionpack/lib/action_controller/metal/instrumentation.rb
index bf74b39ac4b768ba0f855eab0a0b1e57c32f2af7..885ea3fefdd48cd91c51a3f5f0cf2c284c200695 100644
--- a/actionpack/lib/action_controller/metal/instrumentation.rb
+++ b/actionpack/lib/action_controller/metal/instrumentation.rb
@@ -19,6 +19,7 @@ def process_action(*args)
         :controller => self.class.name,
         :action     => self.action_name,
         :params     => request.filtered_parameters,
+        :headers    => request.headers,
         :format     => request.format.ref,
         :method     => request.request_method,
         :path       => request.fullpath
diff --git a/actionpack/test/controller/log_subscriber_test.rb b/actionpack/test/controller/log_subscriber_test.rb
index 6ae33be3c82ac26e8618af4647eed7eaf6dfe240..57cf2dafdf1f32f0ea3b35a128f8b522c2c486ce 100644
--- a/actionpack/test/controller/log_subscriber_test.rb
+++ b/actionpack/test/controller/log_subscriber_test.rb
@@ -183,6 +183,12 @@ def test_append_info_to_payload_is_called_even_with_exception
     assert_equal "test_value", @controller.last_payload[:test_key]
   end
 
+  def test_process_action_headers
+    get :show
+    wait
+    assert_equal "Rails Testing", @controller.last_payload[:headers]['User-Agent']
+  end
+
   def test_process_action_with_filter_parameters
     @request.env["action_dispatch.parameter_filter"] = [:lifo, :amount]