diff --git a/multibuild.py b/multibuild.py
index 900f183..dca87d9 100644
--- a/multibuild.py
+++ b/multibuild.py
@@ -137,7 +137,7 @@ def trigger_child_hooks(buildbotUrl: str, os_codename: str, repository, branch,
         requests.post(request_url, headers=request_headers, data=request_data)
 
 
-def add_parent_step(build_factory, jobname, repository, branch):
+def add_parent_step(build_factory):
     """
     Add a step to the parent build factory that will trigger the child hooks
     """
@@ -155,9 +155,9 @@ def add_parent_step(build_factory, jobname, repository, branch):
             command=[
                 "python",
                 "multibuild.py",
-                jobname,
-                repository,
-                branch,
+                util.Interpolate("%(prop:jobname)s"),
+                util.Property('repository'),
+                util.Property('branch'),
                 "https://buildbot.bitmessage.org",
                 util.Interpolate("%(prop:os_codename)s"),
             ],