diff --git a/charts/aws-event-sources/v0.1.0/questions.yaml b/charts/aws-event-sources/v0.1.0/questions.yaml
index a1cb184645a..7aff6f94c68 100644
--- a/charts/aws-event-sources/v0.1.0/questions.yaml
+++ b/charts/aws-event-sources/v0.1.0/questions.yaml
@@ -32,6 +32,8 @@
     default: "example.com"
     type: string
     required: true
+    $ref:
+      - definitions/interfaces
 - variable: knative.urlScheme
   description: "Specify the Knative URL Scheme"
   label: Knative URL Scheme