diff --git a/src/Octokit.Webhooks/Models/PingEvent/HookType.cs b/src/Octokit.Webhooks/Models/PingEvent/HookType.cs
index cfb25e49..0c4064f4 100644
--- a/src/Octokit.Webhooks/Models/PingEvent/HookType.cs
+++ b/src/Octokit.Webhooks/Models/PingEvent/HookType.cs
@@ -12,4 +12,6 @@ public enum HookType
     Repository,
     [EnumMember(Value = "Organization")]
     Organization,
+    [EnumMember(Value = "App")]
+    App,
 }