diff --git a/actionpack/lib/action_controller/metal/renderers.rb b/actionpack/lib/action_controller/metal/renderers.rb
index 0be07cd1fc76f..f9b226b7c9229 100644
--- a/actionpack/lib/action_controller/metal/renderers.rb
+++ b/actionpack/lib/action_controller/metal/renderers.rb
@@ -71,7 +71,7 @@ def self._write_render_options
     end
 
     add :json do |json, options|
-      json = ActiveSupport::JSON.encode(json, options) unless json.respond_to?(:to_str)
+      json = json.to_json(options) unless json.respond_to?(:to_str)
       json = "#{options[:callback]}(#{json})" unless options[:callback].blank?
       self.content_type ||= Mime::JSON
       self.response_body  = json
diff --git a/actionpack/test/controller/render_json_test.rb b/actionpack/test/controller/render_json_test.rb
index 5958b18d8038b..6dd2a9f23dcb5 100644
--- a/actionpack/test/controller/render_json_test.rb
+++ b/actionpack/test/controller/render_json_test.rb
@@ -9,6 +9,10 @@ def as_json(options={})
       hash.except!(*options[:except]) if options[:except]
       hash
     end
+
+    def to_json(options = {})
+      super :except => [:c, :e]
+    end
   end
 
   class TestController < ActionController::Base
@@ -49,6 +53,10 @@ def render_json_with_render_to_string
     def render_json_with_extra_options
       render :json => JsonRenderable.new, :except => [:c, :e]
     end
+
+    def render_json_without_options
+      render :json => JsonRenderable.new
+    end
   end
 
   tests TestController
@@ -109,4 +117,9 @@ def test_render_json_forwards_extra_options
     assert_equal '{"a":"b"}', @response.body
     assert_equal 'application/json', @response.content_type
   end
+
+  def test_render_json_calls_to_json_from_object
+    get :render_json_without_options
+    assert_equal '{"a":"b"}', @response.body
+  end
 end