diff --git a/dlls/mfplat/mfplat.spec b/dlls/mfplat/mfplat.spec
index 31d3777e87b..5311757d2b7 100644
--- a/dlls/mfplat/mfplat.spec
+++ b/dlls/mfplat/mfplat.spec
@@ -124,6 +124,7 @@
 @ stub MFInitVideoFormat_RGB
 @ stdcall MFInvokeCallback(ptr)
 @ stub MFJoinIoPort
+@ stdcall MFJoinWorkQueue(long long ptr) rtworkq.RtwqJoinWorkQueue
 @ stdcall MFLockPlatform() rtworkq.RtwqLockPlatform
 @ stdcall MFLockWorkQueue(long) rtworkq.RtwqLockWorkQueue
 @ stdcall MFPutWaitingWorkItem(long long ptr ptr) rtworkq.RtwqPutWaitingWorkItem
@@ -158,6 +159,7 @@
 @ stub MFTraceError
 @ stub MFTraceFuncEnter
 @ stub MFUnblockThread
+@ stdcall MFUnjoinWorkQueue(long long) rtworkq.RtwqUnjoinWorkQueue
 @ stdcall MFUnlockPlatform() rtworkq.RtwqUnlockPlatform
 @ stdcall MFUnlockWorkQueue(long) rtworkq.RtwqUnlockWorkQueue
 @ stdcall MFUnwrapMediaType(ptr ptr)
diff --git a/dlls/rtworkq/queue.c b/dlls/rtworkq/queue.c
index 85e84d46d67..32bd75b3469 100644
--- a/dlls/rtworkq/queue.c
+++ b/dlls/rtworkq/queue.c
@@ -1471,3 +1471,17 @@ HRESULT WINAPI RtwqAllocateSerialWorkQueue(DWORD target_queue, DWORD *queue)
     desc.target_queue = target_queue;
     return alloc_user_queue(&desc, queue);
 }
+
+HRESULT WINAPI RtwqJoinWorkQueue(DWORD queue, HANDLE hFile, HANDLE *cookie)
+{
+    FIXME("%#x, %p, %p.\n", queue, hFile, cookie);
+
+    return E_NOTIMPL;
+}
+
+HRESULT WINAPI RtwqUnjoinWorkQueue(DWORD queue, HANDLE cookie)
+{
+    FIXME("%#x, %p.\n", queue, cookie);
+
+    return E_NOTIMPL;
+}
diff --git a/dlls/rtworkq/rtworkq.spec b/dlls/rtworkq/rtworkq.spec
index adc05d679dc..11955ac1a6a 100644
--- a/dlls/rtworkq/rtworkq.spec
+++ b/dlls/rtworkq/rtworkq.spec
@@ -14,7 +14,7 @@
 @ stub RtwqGetWorkQueueMMCSSPriority
 @ stub RtwqGetWorkQueueMMCSSTaskId
 @ stdcall RtwqInvokeCallback(ptr)
-@ stub RtwqJoinWorkQueue
+@ stdcall RtwqJoinWorkQueue(long long ptr)
 @ stdcall RtwqLockPlatform()
 @ stdcall RtwqLockSharedWorkQueue(wstr long ptr ptr)
 @ stdcall RtwqLockWorkQueue(long)
@@ -30,7 +30,7 @@
 @ stdcall RtwqSetLongRunning(long long)
 @ stdcall RtwqShutdown()
 @ stdcall RtwqStartup()
-@ stub RtwqUnjoinWorkQueue
+@ stdcall RtwqUnjoinWorkQueue(long long)
 @ stdcall RtwqUnlockPlatform()
 @ stdcall RtwqUnlockWorkQueue(long)
 @ stub RtwqUnregisterPlatformEvents
diff --git a/include/rtworkq.idl b/include/rtworkq.idl
index 1a452c3edc7..ca6645b862c 100644
--- a/include/rtworkq.idl
+++ b/include/rtworkq.idl
@@ -84,6 +84,7 @@ cpp_quote("HRESULT WINAPI RtwqCancelDeadline(HANDLE request);")
 cpp_quote("HRESULT WINAPI RtwqCancelWorkItem(RTWQWORKITEM_KEY key);")
 cpp_quote("HRESULT WINAPI RtwqCreateAsyncResult(IUnknown *object, IRtwqAsyncCallback *callback, IUnknown *state, IRtwqAsyncResult **result);")
 cpp_quote("HRESULT WINAPI RtwqInvokeCallback(IRtwqAsyncResult *result);")
+cpp_quote("HRESULT WINAPI RtwqJoinWorkQueue(DWORD queue, HANDLE hFile, HANDLE *cookie);")
 cpp_quote("HRESULT WINAPI RtwqLockPlatform(void);")
 cpp_quote("HRESULT WINAPI RtwqLockSharedWorkQueue(const WCHAR *usageclass, LONG priority, DWORD *taskid, DWORD *queue);")
 cpp_quote("HRESULT WINAPI RtwqLockWorkQueue(DWORD queue);")
@@ -96,5 +97,6 @@ cpp_quote("HRESULT WINAPI RtwqSetDeadline2(DWORD queue_id, LONGLONG deadline, LO
 cpp_quote("HRESULT WINAPI RtwqSetLongRunning(DWORD queue_id, BOOL enable);")
 cpp_quote("HRESULT WINAPI RtwqShutdown(void);")
 cpp_quote("HRESULT WINAPI RtwqStartup(void);")
+cpp_quote("HRESULT WINAPI RtwqUnjoinWorkQueue(DWORD queue, HANDLE cookie);")
 cpp_quote("HRESULT WINAPI RtwqUnlockPlatform(void);")
 cpp_quote("HRESULT WINAPI RtwqUnlockWorkQueue(DWORD queue);")