diff --git a/auth/db/auth.php b/auth/db/auth.php
index 5709513..c1cee66 100644
--- a/auth/db/auth.php
+++ b/auth/db/auth.php
@@ -389,6 +389,34 @@ class auth_plugin_db extends auth_plugin_base {
         return 0;
     }
 
+    /**
+    * Confirm the new user as registered. This should normally not be used,
+    * but it may be necessary if the user auth_method is changed to external db
+    * before the user is confirmed.
+    *
+    * @param string $username
+    * @param string $confirmsecret
+    */
+    function user_confirm($username, $confirmsecret = null) {
+        global $DB;
+
+        // Check id the user is in local moodle user table
+        $user = get_complete_user_data('username', $username);
+
+        if (!empty($user)) {
+            if ($user->confirmed) {
+                return AUTH_CONFIRM_ALREADY;
+            } else {
+                // Update local moodle user table
+                $DB->set_field("user", "confirmed", 1, array("id"=>$user->id));
+                $DB->set_field("user", "firstaccess", time(), array("id"=>$user->id));
+                return AUTH_CONFIRM_OK;
+            }
+        } else  {
+            return AUTH_CONFIRM_ERROR;
+        }
+    }
+
     function user_exists($username) {
 
     /// Init result value