diff --git a/lisp/org-latex.el b/lisp/org-latex.el
index be9cf568b..325e76b6d 100644
--- a/lisp/org-latex.el
+++ b/lisp/org-latex.el
@@ -1344,7 +1344,7 @@ LEVEL indicates the default depth for export."
 	      (save-restriction
 		(widen)
 		(goto-char (point-min))
-		(and (re-search-forward "^#\\+LaTeX_CLASS:[ \t]*\\(-[a-zA-Z]+\\)" nil t)
+		(and (re-search-forward "^#\\+LaTeX_CLASS:[ \t]*\\([-a-zA-Z]+\\)" nil t)
 		     (match-string 1))))
 	    (plist-get org-export-latex-options-plist :latex-class)
 	    org-export-latex-default-class)