diff --git a/actionpack/lib/action_view/helpers/form_helper.rb b/actionpack/lib/action_view/helpers/form_helper.rb
index 994fac00149c4..4914ecc5d0fba 100644
--- a/actionpack/lib/action_view/helpers/form_helper.rb
+++ b/actionpack/lib/action_view/helpers/form_helper.rb
@@ -939,7 +939,7 @@ def initialize(object_name, object, template, options, proc)
         end
       end
 
-      (field_helpers - %w(label check_box radio_button fields_for)).each do |selector|
+      (field_helpers - %w(label check_box radio_button fields_for hidden_field)).each do |selector|
         src = <<-end_src
           def #{selector}(method, options = {})  # def text_field(method, options = {})
             @template.send(                      #   @template.send(
@@ -998,6 +998,11 @@ def check_box(method, options = {}, checked_value = "1", unchecked_value = "0")
       def radio_button(method, tag_value, options = {})
         @template.radio_button(@object_name, method, tag_value, objectify_options(options))
       end
+      
+      def hidden_field(method, options = {})
+        @emitted_hidden_id = true if method == :id
+        @template.hidden_field(@object_name, method, objectify_options(options))
+      end
 
       def error_message_on(method, *args)
         @template.error_message_on(@object, method, *args)
@@ -1011,6 +1016,10 @@ def submit(value = "Save changes", options = {})
         @template.submit_tag(value, options.reverse_merge(:id => "#{object_name}_submit"))
       end
 
+      def emitted_hidden_id?
+        @emitted_hidden_id
+      end
+
       private
         def objectify_options(options)
           @default_options.merge(options.merge(:object => @object))
@@ -1045,8 +1054,8 @@ def fields_for_nested_model(name, object, args, block)
             @template.fields_for(name, object, *args, &block)
           else
             @template.fields_for(name, object, *args) do |builder|
-              @template.concat builder.hidden_field(:id)
               block.call(builder)
+              @template.concat builder.hidden_field(:id) unless builder.emitted_hidden_id?
             end
           end
         end
diff --git a/actionpack/test/template/form_helper_test.rb b/actionpack/test/template/form_helper_test.rb
index 357c36d1c0cc7..f22302d3c9055 100644
--- a/actionpack/test/template/form_helper_test.rb
+++ b/actionpack/test/template/form_helper_test.rb
@@ -697,6 +697,26 @@ def test_nested_fields_for_with_an_existing_record_on_a_nested_attributes_one_to
       end
     end
 
+    expected = '<form action="http://www.example.com" method="post">' +
+               '<input name="post[title]" size="30" type="text" id="post_title" value="Hello World" />' +
+               '<input id="post_author_attributes_name" name="post[author_attributes][name]" size="30" type="text" value="author #321" />' +
+               '<input id="post_author_attributes_id" name="post[author_attributes][id]" type="hidden" value="321" />' +
+               '</form>'
+
+    assert_dom_equal expected, output_buffer
+  end
+  
+  def test_nested_fields_for_with_existing_records_on_a_nested_attributes_one_to_one_association_with_explicit_hidden_field_placement
+    @post.author = Author.new(321)
+
+    form_for(:post, @post) do |f|
+      concat f.text_field(:title)
+      f.fields_for(:author) do |af|
+        concat af.hidden_field(:id)
+        concat af.text_field(:name)
+      end
+    end
+    
     expected = '<form action="http://www.example.com" method="post">' +
                '<input name="post[title]" size="30" type="text" id="post_title" value="Hello World" />' +
                '<input id="post_author_attributes_id" name="post[author_attributes][id]" type="hidden" value="321" />' +
@@ -718,6 +738,30 @@ def test_nested_fields_for_with_existing_records_on_a_nested_attributes_collecti
       end
     end
 
+    expected = '<form action="http://www.example.com" method="post">' +
+               '<input name="post[title]" size="30" type="text" id="post_title" value="Hello World" />' +
+               '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" size="30" type="text" value="comment #1" />' +
+               '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="1" />' +
+               '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" size="30" type="text" value="comment #2" />' +
+               '<input id="post_comments_attributes_1_id" name="post[comments_attributes][1][id]" type="hidden" value="2" />' +
+               '</form>'
+
+    assert_dom_equal expected, output_buffer
+  end
+
+  def test_nested_fields_for_with_existing_records_on_a_nested_attributes_collection_association_with_explicit_hidden_field_placement
+    @post.comments = Array.new(2) { |id| Comment.new(id + 1) }
+
+    form_for(:post, @post) do |f|
+      concat f.text_field(:title)
+      @post.comments.each do |comment|
+        f.fields_for(:comments, comment) do |cf|
+          concat cf.hidden_field(:id)
+          concat cf.text_field(:name)
+        end
+      end
+    end
+    
     expected = '<form action="http://www.example.com" method="post">' +
                '<input name="post[title]" size="30" type="text" id="post_title" value="Hello World" />' +
                '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="1" />' +
@@ -764,8 +808,8 @@ def test_nested_fields_for_with_existing_and_new_records_on_a_nested_attributes_
 
     expected = '<form action="http://www.example.com" method="post">' +
                '<input name="post[title]" size="30" type="text" id="post_title" value="Hello World" />' +
-               '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="321" />' +
                '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" size="30" type="text" value="comment #321" />' +
+               '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="321" />' +
                '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" size="30" type="text" value="new comment" />' +
                '</form>'
 
@@ -799,10 +843,10 @@ def test_nested_fields_for_with_existing_records_on_a_supplied_nested_attributes
 
     expected = '<form action="http://www.example.com" method="post">' +
                '<input name="post[title]" size="30" type="text" id="post_title" value="Hello World" />' +
-               '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="1" />' +
                '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" size="30" type="text" value="comment #1" />' +
-               '<input id="post_comments_attributes_1_id" name="post[comments_attributes][1][id]" type="hidden" value="2" />' +
+               '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="1" />' +
                '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" size="30" type="text" value="comment #2" />' +
+               '<input id="post_comments_attributes_1_id" name="post[comments_attributes][1][id]" type="hidden" value="2" />' +
                '</form>'
 
     assert_dom_equal expected, output_buffer
@@ -822,8 +866,8 @@ def test_nested_fields_for_on_a_nested_attributes_collection_association_yields_
 
     expected = '<form action="http://www.example.com" method="post">' +
                '<input name="post[title]" size="30" type="text" id="post_title" value="Hello World" />' +
-               '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="321" />' +
                '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" size="30" type="text" value="comment #321" />' +
+               '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="321" />' +
                '<input id="post_comments_attributes_1_name" name="post[comments_attributes][1][name]" size="30" type="text" value="new comment" />' +
                '</form>'
 
@@ -841,8 +885,8 @@ def test_nested_fields_for_with_child_index_option_override_on_a_nested_attribut
     end
 
     expected = '<form action="http://www.example.com" method="post">' +
-               '<input id="post_comments_attributes_abc_id" name="post[comments_attributes][abc][id]" type="hidden" value="321" />' +
                '<input id="post_comments_attributes_abc_name" name="post[comments_attributes][abc][name]" size="30" type="text" value="comment #321" />' +
+               '<input id="post_comments_attributes_abc_id" name="post[comments_attributes][abc][id]" type="hidden" value="321" />' +
                '</form>'
 
     assert_dom_equal expected, output_buffer
@@ -876,18 +920,18 @@ def test_nested_fields_uses_unique_indices_for_different_collection_associations
     end
 
     expected = '<form action="http://www.example.com" method="post">' +
-               '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="321" />' +
                '<input id="post_comments_attributes_0_name" name="post[comments_attributes][0][name]" size="30" type="text" value="comment #321" />' +
-               '<input id="post_comments_attributes_0_relevances_attributes_0_id" name="post[comments_attributes][0][relevances_attributes][0][id]" type="hidden" value="314" />' +
                '<input id="post_comments_attributes_0_relevances_attributes_0_value" name="post[comments_attributes][0][relevances_attributes][0][value]" size="30" type="text" value="commentrelevance #314" />' +
-               '<input id="post_tags_attributes_0_id" name="post[tags_attributes][0][id]" type="hidden" value="123" />' +
+               '<input id="post_comments_attributes_0_relevances_attributes_0_id" name="post[comments_attributes][0][relevances_attributes][0][id]" type="hidden" value="314" />' +
+               '<input id="post_comments_attributes_0_id" name="post[comments_attributes][0][id]" type="hidden" value="321" />' +
                '<input id="post_tags_attributes_0_value" name="post[tags_attributes][0][value]" size="30" type="text" value="tag #123" />' +
-               '<input id="post_tags_attributes_0_relevances_attributes_0_id" name="post[tags_attributes][0][relevances_attributes][0][id]" type="hidden" value="3141" />' +
                '<input id="post_tags_attributes_0_relevances_attributes_0_value" name="post[tags_attributes][0][relevances_attributes][0][value]" size="30" type="text" value="tagrelevance #3141" />' +
-               '<input id="post_tags_attributes_1_id" name="post[tags_attributes][1][id]" type="hidden" value="456" />' +
+               '<input id="post_tags_attributes_0_relevances_attributes_0_id" name="post[tags_attributes][0][relevances_attributes][0][id]" type="hidden" value="3141" />' +
+               '<input id="post_tags_attributes_0_id" name="post[tags_attributes][0][id]" type="hidden" value="123" />' +
                '<input id="post_tags_attributes_1_value" name="post[tags_attributes][1][value]" size="30" type="text" value="tag #456" />' +
-               '<input id="post_tags_attributes_1_relevances_attributes_0_id" name="post[tags_attributes][1][relevances_attributes][0][id]" type="hidden" value="31415" />' +
                '<input id="post_tags_attributes_1_relevances_attributes_0_value" name="post[tags_attributes][1][relevances_attributes][0][value]" size="30" type="text" value="tagrelevance #31415" />' +
+               '<input id="post_tags_attributes_1_relevances_attributes_0_id" name="post[tags_attributes][1][relevances_attributes][0][id]" type="hidden" value="31415" />' +
+               '<input id="post_tags_attributes_1_id" name="post[tags_attributes][1][id]" type="hidden" value="456" />' +
                '</form>'
 
     assert_dom_equal expected, output_buffer