diff --git a/lib/validates_timeliness/attribute_methods.rb b/lib/validates_timeliness/attribute_methods.rb
index e8bf9c9..7f89642 100644
--- a/lib/validates_timeliness/attribute_methods.rb
+++ b/lib/validates_timeliness/attribute_methods.rb
@@ -20,6 +20,11 @@ module ValidatesTimeliness
         :datetime
       end
 
+      def undefine_attribute_methods
+        super
+        undefine_timeliness_attribute_methods
+      end
+
       protected
 
       def define_timeliness_methods(before_type_cast=false)
@@ -65,6 +70,12 @@ module ValidatesTimeliness
       def generated_timeliness_methods
         @generated_timeliness_methods ||= Module.new.tap { |m| include(m) }
       end
+
+      def undefine_timeliness_attribute_methods
+        generated_timeliness_methods.module_eval do
+          instance_methods.each { |m| undef_method(m) }
+        end
+      end
     end
 
     def _timeliness_raw_value_for(attr_name)
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 73835a3..4cc5ff3 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -88,8 +88,7 @@ RSpec.configure do |c|
   c.include(ModelHelpers)
   c.include(ConfigHelper)
   c.before do
-    Person.reset_callbacks(:validate)
-    PersonWithShim.timeliness_validated_attributes = []
-    Person._validators.clear
+    reset_validation_setup_for(Person)
+    reset_validation_setup_for(PersonWithShim)
   end
 end
diff --git a/spec/support/config_helper.rb b/spec/support/config_helper.rb
index 6b8889f..2411cf6 100644
--- a/spec/support/config_helper.rb
+++ b/spec/support/config_helper.rb
@@ -10,6 +10,16 @@ module ConfigHelper
     ValidatesTimeliness.send(:"#{preference_name}=", old_value)
   end
 
+  def reset_validation_setup_for(model_class)
+    model_class.reset_callbacks(:validate)
+    model_class._validators.clear
+    model_class.timeliness_validated_attributes = [] if model_class.respond_to?(:timeliness_validated_attributes)
+    model_class.undefine_attribute_methods
+    # This is a hack to avoid a disabled super method error message after an undef
+    model_class.instance_variable_set(:@generated_attribute_methods, nil)
+    model_class.instance_variable_set(:@generated_timeliness_methods, nil)
+  end
+
   module ClassMethods
     def with_config(preference_name, temporary_value)
       original_config_value = ValidatesTimeliness.send(preference_name)
diff --git a/spec/validates_timeliness/attribute_methods_spec.rb b/spec/validates_timeliness/attribute_methods_spec.rb
index f600025..7d4576c 100644
--- a/spec/validates_timeliness/attribute_methods_spec.rb
+++ b/spec/validates_timeliness/attribute_methods_spec.rb
@@ -40,6 +40,21 @@ describe ValidatesTimeliness::AttributeMethods do
       e.redefined_birth_date_called.should be_true
     end
 
+    it 'should be undefined if model class has dynamic attribute methods reset' do
+      # Force method definitions
+      PersonWithShim.validates_date :birth_date
+      r = PersonWithShim.new
+      r.birth_date = Time.now
+
+      write_method = RUBY_VERSION < '1.9' ? 'birth_date=' : :birth_date=
+
+      PersonWithShim.send(:generated_timeliness_methods).instance_methods.should include(write_method)
+
+      PersonWithShim.undefine_attribute_methods 
+
+      PersonWithShim.send(:generated_timeliness_methods).instance_methods.should_not include(write_method)
+    end
+
     context "with plugin parser" do
       with_config(:use_plugin_parser, true)