diff --git a/gnu/services.scm b/gnu/services.scm
index 5479bfa..fc3e17e 100644
--- a/gnu/services.scm
+++ b/gnu/services.scm
@@ -352,11 +352,18 @@ ACTIVATION-SCRIPT-TYPE."
 
 (define (second-argument a b) b)
 
+(define (gexps->activation-system-entry gexps)
+  "Return a directory entry to add to the result of the 'system' derivation."
+  (mlet %store-monad ((script (activation-script gexps)))
+    (return `(("activate" ,script)))))
+
 (define activation-service-type
   (service-type (name 'activate)
                 (extensions
                  (list (service-extension boot-service-type
-                                          gexps->activation-gexp)))
+                                          gexps->activation-gexp)
+                       (service-extension system-service-type
+                                          gexps->activation-system-entry)))
                 (compose append)
                 (extend second-argument)))