diff --git a/Libraries/LibWeb/HTML/MessagePort.cpp b/Libraries/LibWeb/HTML/MessagePort.cpp
index a14ed948970..f9d878a7702 100644
--- a/Libraries/LibWeb/HTML/MessagePort.cpp
+++ b/Libraries/LibWeb/HTML/MessagePort.cpp
@@ -37,13 +37,14 @@ static HashTable<GC::RawPtr<MessagePort>>& all_message_ports()
     return ports;
 }
 
-GC::Ref<MessagePort> MessagePort::create(JS::Realm& realm)
+GC::Ref<MessagePort> MessagePort::create(JS::Realm& realm, HTML::TransferType primary_interface)
 {
-    return realm.create<MessagePort>(realm);
+    return realm.create<MessagePort>(realm, primary_interface);
 }
 
-MessagePort::MessagePort(JS::Realm& realm)
+MessagePort::MessagePort(JS::Realm& realm, HTML::TransferType primary_interface)
     : DOM::EventTarget(realm)
+    , m_primary_interface(primary_interface)
 {
     all_message_ports().set(this);
 }
diff --git a/Libraries/LibWeb/HTML/MessagePort.h b/Libraries/LibWeb/HTML/MessagePort.h
index 24e3bbeccbf..94817214818 100644
--- a/Libraries/LibWeb/HTML/MessagePort.h
+++ b/Libraries/LibWeb/HTML/MessagePort.h
@@ -20,13 +20,14 @@
 namespace Web::HTML {
 
 // https://html.spec.whatwg.org/multipage/web-messaging.html#message-ports
-class MessagePort final : public DOM::EventTarget
+class MessagePort final
+    : public DOM::EventTarget
     , public Bindings::Transferable {
     WEB_PLATFORM_OBJECT(MessagePort, DOM::EventTarget);
     GC_DECLARE_ALLOCATOR(MessagePort);
 
 public:
-    [[nodiscard]] static GC::Ref<MessagePort> create(JS::Realm&);
+    [[nodiscard]] static GC::Ref<MessagePort> create(JS::Realm&, HTML::TransferType primary_interface = HTML::TransferType::MessagePort);
 
     static void for_each_message_port(Function<void(MessagePort&)>);
 
@@ -59,14 +60,14 @@ public:
     // ^Transferable
     virtual WebIDL::ExceptionOr<void> transfer_steps(HTML::TransferDataHolder&) override;
     virtual WebIDL::ExceptionOr<void> transfer_receiving_steps(HTML::TransferDataHolder&) override;
-    virtual HTML::TransferType primary_interface() const override { return HTML::TransferType::MessagePort; }
+    virtual HTML::TransferType primary_interface() const override { return m_primary_interface; }
 
     void set_worker_event_target(GC::Ref<DOM::EventTarget>);
 
     WebIDL::ExceptionOr<void> message_port_post_message_steps(GC::Ptr<MessagePort> target_port, JS::Value message, StructuredSerializeOptions const& options);
 
 private:
-    explicit MessagePort(JS::Realm&);
+    explicit MessagePort(JS::Realm&, HTML::TransferType primary_interface);
 
     virtual void initialize(JS::Realm&) override;
     virtual void finalize() override;
@@ -79,6 +80,8 @@ private:
     ErrorOr<void> send_message_on_transport(SerializedTransferRecord const&);
     void read_from_transport();
 
+    HTML::TransferType m_primary_interface { HTML::TransferType::MessagePort };
+
     // The HTML spec implies(!) that this is MessagePort.[[RemotePort]]
     GC::Ptr<MessagePort> m_remote_port;