diff --git a/.taskcluster.yml b/.taskcluster.yml
index c43a61e7fbe..1a6cf1da49f 100644
--- a/.taskcluster.yml
+++ b/.taskcluster.yml
@@ -26,7 +26,7 @@ tasks:
           taskclusterProxy: true
         env:
           DECISION_TASK_ID: {$eval: as_slugid("decision_task")}
-          GITHUB_EVENT: {$json: event}
+          GITHUB_EVENT: {$json: {$eval: event}}
         command:
           - /bin/bash
           - '--login'