diff --git a/lib/jekyll/excerpt.rb b/lib/jekyll/excerpt.rb
index d270624c..18d456ea 100644
--- a/lib/jekyll/excerpt.rb
+++ b/lib/jekyll/excerpt.rb
@@ -48,7 +48,7 @@ module Jekyll
     #
     # Returns the relative_path for the doc this excerpt belongs to with #excerpt appended
     def relative_path
-      File.join(doc.relative_path, "#excerpt")
+      @relative_path ||= File.join(doc.relative_path, "#excerpt")
     end
 
     # Check if excerpt includes a string