diff --git a/lib/factory_girl/evaluator.rb b/lib/factory_girl/evaluator.rb
index 54f56c8..8d55378 100644
--- a/lib/factory_girl/evaluator.rb
+++ b/lib/factory_girl/evaluator.rb
@@ -11,13 +11,21 @@ module FactoryGirl
         end
       end
     end
-    undef_method(:id) if method_defined?(:id)
+
+    private_instance_methods.each do |method|
+      undef_method(method) unless method =~ /^__|initialize/
+    end
 
     def initialize(build_strategy, overrides = {})
       @build_strategy    = build_strategy
       @overrides         = overrides
       @cached_attributes = overrides
 
+      singleton = class << self; self end
+      @overrides.each do |name, value|
+        singleton.send :define_method, name, lambda { value }
+      end
+
       @build_strategy.add_observer(CallbackRunner.new(self.class.callbacks, self))
     end
 
diff --git a/spec/acceptance/attribute_existing_on_object_spec.rb b/spec/acceptance/attribute_existing_on_object_spec.rb
index 4a776f0..91fb58f 100644
--- a/spec/acceptance/attribute_existing_on_object_spec.rb
+++ b/spec/acceptance/attribute_existing_on_object_spec.rb
@@ -19,3 +19,50 @@ describe "declaring attributes on a Factory that are private methods on Object"
   its(:link)   { should == "http://example.com" }
   its(:sleep)  { should == -5 }
 end
+
+describe "assigning overrides that are also private methods on object" do
+  before do
+    define_model("Website",  :format => :string, :y => :integer, :more_format => :string, :some_funky_method => :string)
+
+    Object.class_eval do
+      private
+      def some_funky_method(args)
+      end
+    end
+
+    FactoryGirl.define do
+      factory :website do
+        more_format { "format: #{format}" }
+      end
+    end
+  end
+
+  after do
+    Object.send(:undef_method, :some_funky_method)
+  end
+
+  subject { FactoryGirl.build(:website, :format => "Great", :y => 12345, :some_funky_method => "foobar!") }
+  its(:format)            { should == "Great" }
+  its(:y)                 { should == 12345 }
+  its(:more_format)       { should == "format: Great" }
+  its(:some_funky_method) { should == "foobar!" }
+end
+
+describe "accessing methods from the instance within a dynamic attribute that is also a private method on object" do
+  before do
+    define_model("Website", :more_format => :string) do
+      def format
+        "This is an awesome format"
+      end
+    end
+
+    FactoryGirl.define do
+      factory :website do
+        more_format { "format: #{format}" }
+      end
+    end
+  end
+
+  subject           { FactoryGirl.build(:website) }
+  its(:more_format) { should == "format: This is an awesome format" }
+end