diff --git a/mod/calendar/class/Admin.php b/mod/calendar/class/Admin.php
index f7102c713..7a9fb0777 100644
--- a/mod/calendar/class/Admin.php
+++ b/mod/calendar/class/Admin.php
@@ -213,6 +213,9 @@ public static function event_form(Calendar_Event $event, $suggest = false)
             $form->setMatch('show_busy', $event->show_busy);
             $form->setLabel('show_busy', 'Show busy');
         }
+        if (ALLOW_CAPTCHA) {
+            $form->addTplTag('CAPTCHA_IMAGE', Captcha::get());
+        }
 
         if ($suggest) {
             $form->addSubmit('save', 'Suggest event');