diff --git a/lib/flexmock/partial_mock.rb b/lib/flexmock/partial_mock.rb
index 3135d23..b6743fa 100755
--- a/lib/flexmock/partial_mock.rb
+++ b/lib/flexmock/partial_mock.rb
@@ -194,7 +194,8 @@ def initialize_stub(recorder, expectations_block)
             super(*args, &block)
           end
         end
-        @obj.prepend @initialize_override
+        override = @initialize_override
+        @obj.class_eval { prepend override }
       end
       if expectations_block
         @initialize_expectation_blocks    << expectations_block