diff --git a/src/hotspot/share/runtime/thread.hpp b/src/hotspot/share/runtime/thread.hpp
index d5fd9320817..e381da6bc8c 100644
--- a/src/hotspot/share/runtime/thread.hpp
+++ b/src/hotspot/share/runtime/thread.hpp
@@ -83,7 +83,6 @@ class javaVFrame;
 class DeoptResourceMark;
 class jvmtiDeferredLocalVariableSet;
 
-class GCTaskQueue;
 class ThreadClosure;
 class ICRefillVerifier;
 class IdealGraphPrinter;
@@ -108,7 +107,6 @@ class WorkerThread;
 //       - ConcurrentGCThread
 //       - WorkerThread
 //         - GangWorker
-//         - GCTaskThread
 //     - WatcherThread
 //     - JfrThreadSampler
 //