diff --git a/etc/taskcluster/macos/config/roster b/etc/taskcluster/macos/config/roster
index f4e16de6609..6a2ace9eeef 100644
--- a/etc/taskcluster/macos/config/roster
+++ b/etc/taskcluster/macos/config/roster
@@ -2,3 +2,5 @@ mac1:
     host: servo-tc-mac1.servo.org
 mac2:
     host: servo-tc-mac2.servo.org
+mac3:
+    host: servo-tc-mac3.servo.org
\ No newline at end of file