diff --git a/specs.json b/specs.json
index a107878..c3fb68f 100644
--- a/specs.json
+++ b/specs.json
@@ -34,6 +34,7 @@
       "id": "string",
       "referTo": "string",
       "referredBy": "string",
+      "referredByDisplayName": "string",
       "headers": "object",
       "actionHook": "object|string",
       "eventHook": "object|string"
diff --git a/test/jambonz-verb-test.js b/test/jambonz-verb-test.js
index 716fb45..c355aa6 100644
--- a/test/jambonz-verb-test.js
+++ b/test/jambonz-verb-test.js
@@ -440,6 +440,12 @@ test("validate correct verbs", async (t) => {
       "referTo": "+15083084809",
       "actionHook": "/action"
     },
+    {
+      "verb": "sip:refer",
+      "referTo": "+15083084809",
+      "referredByDisplayName": "Alice",
+      "actionHook": "/action"
+    },
     {
       "verb": "tag",
       "data": {