diff --git a/dlls/ntoskrnl.exe/ntoskrnl.exe.spec b/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
index 50c442ad077..c004a964aa4 100644
--- a/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
+++ b/dlls/ntoskrnl.exe/ntoskrnl.exe.spec
@@ -1182,6 +1182,7 @@
 @ stdcall RtlUnicodeToOemN(ptr long ptr ptr long) ntdll.RtlUnicodeToOemN
 @ stub RtlUnlockBootStatusData
 @ stdcall -register RtlUnwind(ptr ptr ptr ptr) ntdll.RtlUnwind
+@ stdcall -arch=x86_64 RtlUnwindEx(ptr ptr ptr ptr ptr ptr) ntdll.RtlUnwindEx
 @ stdcall RtlUpcaseUnicodeChar(long) ntdll.RtlUpcaseUnicodeChar
 @ stdcall RtlUpcaseUnicodeString(ptr ptr long) ntdll.RtlUpcaseUnicodeString
 @ stdcall RtlUpcaseUnicodeStringToAnsiString(ptr ptr long) ntdll.RtlUpcaseUnicodeStringToAnsiString