diff --git a/contrib/lisp/ox-koma-letter.el b/contrib/lisp/ox-koma-letter.el
index 548204681..66394689d 100644
--- a/contrib/lisp/ox-koma-letter.el
+++ b/contrib/lisp/ox-koma-letter.el
@@ -748,7 +748,8 @@ holding export options."
                 (if (symbolp with-subject) with-subject
                   (mapconcat #'symbol-name with-subject ","))))
       ;; Hyperref.
-      (format-spec hyperref-template spec)
+      (and (stringp hyperref-template)
+	   (format-spec hyperref-template spec))
       ;; Document start.
       "\\begin{document}\n\n"
       ;; Subject and title.