diff --git a/activemodel/lib/active_model/errors.rb b/activemodel/lib/active_model/errors.rb
index 1431228..4e8c470 100644
--- a/activemodel/lib/active_model/errors.rb
+++ b/activemodel/lib/active_model/errors.rb
@@ -170,6 +170,16 @@ module ActiveModel
       self
     end
 
+    # Represents an error message. Contains the model instance (+base+), the +attribute+ and the +options+
+    # passed to validators.
+    class ErrorMessage < String
+      attr_reader :base, :attribute, :options
+      def initialize(message, base, attribute, options)
+        super(message)
+        @base, @attribute, @options = base, attribute, options
+      end
+    end
+
     # Adds +message+ to the error messages on +attribute+, which will be returned on a call to
     # <tt>on(attribute)</tt> for the same attribute. More than one error can be added to the same
     # +attribute+ in which case an array will be returned on a call to <tt>on(attribute)</tt>.
@@ -245,7 +255,8 @@ module ActiveModel
           options = { :default => "%{attribute} %{message}", :attribute => attr_name }
 
           messages.each do |m|
-            full_messages << I18n.t(:"errors.format", options.merge(:message => m))
+            full_messages << ((m.is_a?(ErrorMessage) && m.options[:full_message]) ?
+              m : I18n.t(:"errors.format", options.merge(:message => m)))
           end
         end
       end
@@ -279,13 +290,15 @@ module ActiveModel
     # <li><tt>errors.messages.blank</tt></li>
     # </ol>
     def generate_message(attribute, type = :invalid, options = {})
-      type = options.delete(:message) if options[:message].is_a?(Symbol)
+      original_options = options.clone
+      message = [options.delete(:full_message), options.delete(:message)].compact[0]
+      message, type = nil, message if message.is_a? Symbol
 
       if options[:default]
         ActiveSupport::Deprecation.warn \
           "ActiveModel::Errors#generate_message(attributes, custom_message) has been deprecated.\n" +
           "Use ActiveModel::Errors#generate_message(attributes, :message => 'your message') instead."
-        options[:message] = options.delete(:default)
+        message = options.delete(:default)
       end
 
       defaults = @base.class.lookup_ancestors.map do |klass|
@@ -293,12 +306,11 @@ module ActiveModel
           :"#{@base.class.i18n_scope}.errors.models.#{klass.model_name.underscore}.#{type}" ]
       end
 
-      defaults << options.delete(:message)
+      defaults << message if message
       defaults << :"#{@base.class.i18n_scope}.errors.messages.#{type}"
       defaults << :"errors.attributes.#{attribute}.#{type}"
       defaults << :"errors.messages.#{type}"
 
-      defaults.compact!
       defaults.flatten!
 
       key = defaults.shift
@@ -311,7 +323,7 @@ module ActiveModel
         :value => value
       }.merge(options)
 
-      I18n.translate(key, options)
+      ErrorMessage.new I18n.translate(key, options), @base, attribute, original_options
     end
   end
 end