diff --git a/src/main/messages.cl b/src/main/messages.cl
index 035f4f4..45d458a 100644
--- a/src/main/messages.cl
+++ b/src/main/messages.cl
@@ -380,6 +380,7 @@ used to call `reinitialize-instance'."))
     (set-cookie "Set-Cookie"
       (format stream "~:{~A~@[=~A~]~^;~:}" set-cookie)))
   (when (slot-boundp message 'entity)
+    (update-entity-headers (http-message-entity message))
     (render-entity-headers (http-message-entity message) stream)
     (http-terpri stream)
     (unless (or (= (response-status-code message) +HTTP-Code-Not-Modified+)