diff --git a/actionpack/lib/action_view/helpers/form_helper.rb b/actionpack/lib/action_view/helpers/form_helper.rb
index 81c9c88..668ab30 100644
--- a/actionpack/lib/action_view/helpers/form_helper.rb
+++ b/actionpack/lib/action_view/helpers/form_helper.rb
@@ -505,7 +505,7 @@ module ActionView
 
       # Returns a label tag tailored for labelling an input field for a specified attribute (identified by +method+) on an object
       # assigned to the template (identified by +object+). The text of label will default to the attribute name unless a translation
-      # is found in the current I18n locale (through views.labels.<modelname>.<attribute>) or you specify it explicitly. 
+      # is found in the current I18n locale (through views.labels.<modelname>.<attribute>) or you specify it explicitly.
       # Additional options on the label tag can be passed as a hash with +options+. These options will be tagged
       # onto the HTML as an HTML element attribute as in the example shown, except for the <tt>:value</tt> option, which is designed to
       # target labels for radio_button tags (where the value is used in the ID of the input tag).
@@ -1058,7 +1058,7 @@ module ActionView
       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))
@@ -1110,7 +1110,7 @@ module ActionView
         end
 
         def fields_for_nested_model(name, object, args, block)
-          if object.new_record?
+          if object.respond_to?(:new_record) && object.new_record?
             @template.fields_for(name, object, *args, &block)
           else
             @template.fields_for(name, object, *args) do |builder|