diff --git a/lib/slimmer/template.rb b/lib/slimmer/template.rb
index <HASH>..<HASH> 100644
--- a/lib/slimmer/template.rb
+++ b/lib/slimmer/template.rb
@@ -7,7 +7,7 @@ module Slimmer
     module ClassMethods
       def slimmer_template template_name
         after_filter do
-          response.headers[Slimmer::TEMPLATE_HEADER] = template_name.to_s
+          response.headers[Slimmer::Headers::TEMPLATE_HEADER] = template_name.to_s
         end
       end
     end
Fix missed reference to old header constant location