diff --git a/src/pretix/base/services/mail.py b/src/pretix/base/services/mail.py
index 8397523174..56bc7036f2 100644
--- a/src/pretix/base/services/mail.py
+++ b/src/pretix/base/services/mail.py
@@ -116,10 +116,10 @@ def mail(email: str, subject: str, template: Union[str, LazyI18nString],
                 body_plain += signature
                 body_plain += "\r\n\r\n-- \r\n"
 
-            body_plain += _(
-                "You are receiving this email because you placed an order for {event}."
-            ).format(event=event.name)
             if order:
+                body_plain += _(
+                    "You are receiving this email because you placed an order for {event}."
+                ).format(event=event.name)
                 htmlctx['order'] = order
                 body_plain += "\r\n"
                 body_plain += _(