diff --git a/Include/internal/pycore_pythread.h b/Include/internal/pycore_pythread.h
@@ -78,7 +78,7 @@ struct _pythread_runtime_state {
     } stubs;
 #endif
 
-    // Linked list of ThreadHandleObjects
+    // Linked list of struct _PyThread_handle_data
     struct llist_node handles;
 };
 
@@ -153,6 +153,31 @@ PyAPI_FUNC(int) PyThread_join_thread(PyThread_handle_t);
  */
 PyAPI_FUNC(int) PyThread_detach_thread(PyThread_handle_t);
 
+
+/******************/
+/* thread handles */
+/******************/
+
+// Handles transition from RUNNING to one of JOINED, DETACHED, or INVALID (post
+// fork).
+typedef enum {
+    THREAD_HANDLE_RUNNING = 1,
+    THREAD_HANDLE_JOINED = 2,
+    THREAD_HANDLE_DETACHED = 3,
+    THREAD_HANDLE_INVALID = 4,
+} _PyThreadHandleState;
+
+extern PyTypeObject _PyThreadHandle_Type;
+
+extern PyObject * _PyThreadHandle_NewObject(void);
+extern _PyEventRc * _PyThreadHandle_GetExitingEvent(PyObject *);
+extern void _PyThreadHandle_SetStarted(
+    PyObject *obj,
+    PyThread_handle_t handle,
+    PyThread_ident_t ident
+);
+
+
 #ifdef __cplusplus
 }
 #endif

@@ -524,6 +524,7 @@ OBJECT_OBJS=	\
 		Objects/setobject.o \
 		Objects/sliceobject.o \
 		Objects/structseq.o \
+		Objects/threadhandleobject.o \
 		Objects/tupleobject.o \
 		Objects/typeobject.o \
 		Objects/typevarobject.o \