diff --git a/client-ts/Microsoft.AspNetCore.SignalR.Test.Server/ComplexObject.cs b/client-ts/Microsoft.AspNetCore.SignalR.Test.Server/ComplexObject.cs
index 8624b6d246..7ae481c348 100644
--- a/client-ts/Microsoft.AspNetCore.SignalR.Test.Server/ComplexObject.cs
+++ b/client-ts/Microsoft.AspNetCore.SignalR.Test.Server/ComplexObject.cs
@@ -1,6 +1,8 @@
 // Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
+using System;
+
 namespace Microsoft.AspNetCore.SignalR.Test.Server
 {
     public class ComplexObject
@@ -8,5 +10,6 @@ namespace Microsoft.AspNetCore.SignalR.Test.Server
         public string String { get; set; }
         public int[] IntArray { get; set; }
         public byte[] ByteArray { get; set; }
+        public Guid GUID { get; set; }
     }
 }
\ No newline at end of file
diff --git a/client-ts/Microsoft.AspNetCore.SignalR.Test.Server/wwwroot/js/hubConnectionTests.js b/client-ts/Microsoft.AspNetCore.SignalR.Test.Server/wwwroot/js/hubConnectionTests.js
index 84eadbbc97..68d4698959 100644
--- a/client-ts/Microsoft.AspNetCore.SignalR.Test.Server/wwwroot/js/hubConnectionTests.js
+++ b/client-ts/Microsoft.AspNetCore.SignalR.Test.Server/wwwroot/js/hubConnectionTests.js
@@ -301,17 +301,30 @@ describe('hubConnection', function () {
                     IntArray: [0x01, 0x02, 0x03, 0xff],
                     ByteArray: protocol.name == "json"
                         ? btoa([0xff, 0x03, 0x02, 0x01])
-                        : new Uint8Array([0xff, 0x03, 0x02, 0x01])
+                        : new Uint8Array([0xff, 0x03, 0x02, 0x01]),
+                    GUID: protocol.name == "json"
+                        ? "00010203-0405-0607-0706-050403020100"
+                        : new Uint8Array([0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x07, 0x06, 0x05, 0x04, 0x03, 0x02, 0x01, 0x00])
                 };
 
                 hubConnection.start().then(function () {
                     return hubConnection.invoke('EchoComplexObject', complexObject);
                 })
                 .then(function (value) {
-                    // msgpack creates a Buffer for byte arrays and jasmine fails to compare a Buffer
-                    // and a Uint8Array even though Buffer instances are also Uint8Array instances
                     if (protocol.name == "messagepack") {
+                        // msgpack creates a Buffer for byte arrays and jasmine fails to compare a Buffer
+                        // and a Uint8Array even though Buffer instances are also Uint8Array instances
                         value.ByteArray = new Uint8Array(value.ByteArray);
+
+                        // GUIDs are serialized as raw type which is a string containing bytes which need to
+                        // be extracted. Note that with msgpack5 the original bytes will be encoded with utf8
+                        // and needs to be decoded. To not go into utf8 encoding intricacies the test uses values
+                        // less than 0x80.
+                        let guidBytes = [];
+                        for (let i = 0; i < value.GUID.length; i++) {
+                            guidBytes.push(value.GUID.charCodeAt(i));
+                        }
+                        value.GUID = new Uint8Array(guidBytes);
                     }
                     expect(value).toEqual(complexObject);
                 })