diff --git a/emacs/notmuch-address.el b/emacs/notmuch-address.el
index fde3c1b2..e2af8792 100644
--- a/emacs/notmuch-address.el
+++ b/emacs/notmuch-address.el
@@ -23,11 +23,13 @@
 
 ;;
 
-(defcustom notmuch-address-command "notmuch-addresses"
+(defcustom notmuch-address-command nil
   "The command which generates possible addresses. It must take a
 single argument and output a list of possible matches, one per
-line."
-  :type 'string
+line. The default value of nil disables address completion."
+  :type '(radio
+	  (const :tag "Disable address completion" nil)
+	  (string :tag "Use external completion command" "notmuch-addresses"))
   :group 'notmuch-send
   :group 'notmuch-external)
 
@@ -55,10 +57,12 @@ to know how address selection is made by default."
 (defvar notmuch-address-history nil)
 
 (defun notmuch-address-message-insinuate ()
+  (message "calling notmuch-address-message-insinuate is no longer needed"))
+
+(defun notmuch-address-setup ()
   (unless (memq notmuch-address-message-alist-member message-completion-alist)
     (setq message-completion-alist
 	  (push notmuch-address-message-alist-member message-completion-alist))))
-
 (defun notmuch-address-options (original)
   (process-lines notmuch-address-command original))
 
@@ -109,11 +113,4 @@ to know how address selection is made by default."
 			   (not (file-directory-p bin))))
 	      (throw 'found-command bin))))))))
 
-;; If we can find the program specified by `notmuch-address-command',
-;; insinuate ourselves into `message-mode'.
-(when (notmuch-address-locate-command notmuch-address-command)
-  (notmuch-address-message-insinuate))
-
-;;
-
 (provide 'notmuch-address)
diff --git a/emacs/notmuch-mua.el b/emacs/notmuch-mua.el
index 57465b20..fd98ea41 100644
--- a/emacs/notmuch-mua.el
+++ b/emacs/notmuch-mua.el
@@ -269,7 +269,9 @@ Note that these functions use `mail-citation-hook' if that is non-nil."
   (set-buffer-modified-p nil))
 
 (define-derived-mode notmuch-message-mode message-mode "Message[Notmuch]"
-  "Notmuch message composition mode. Mostly like `message-mode'")
+  "Notmuch message composition mode. Mostly like `message-mode'"
+  (when notmuch-address-command
+    (notmuch-address-setup)))
 
 (define-key notmuch-message-mode-map (kbd "C-c C-c") #'notmuch-mua-send-and-exit)
 (define-key notmuch-message-mode-map (kbd "C-c C-s") #'notmuch-mua-send)