diff --git a/reactos/lib/kernel32/kernel32.def b/reactos/lib/kernel32/kernel32.def
index e76e2316eb0..bdaabdc7f55 100644
--- a/reactos/lib/kernel32/kernel32.def
+++ b/reactos/lib/kernel32/kernel32.def
@@ -586,6 +586,7 @@ IsDebuggerPresent@0
 IsProcessInJob@12
 IsProcessorFeaturePresent@4
 IsSystemResumeAutomatic@0
+IsThreadAFiber@0
 IsValidCodePage@4
 IsValidLanguageGroup@8
 IsValidLocale@8
diff --git a/reactos/lib/kernel32/thread/fiber.c b/reactos/lib/kernel32/thread/fiber.c
index aefd2d41542..10881d3d104 100644
--- a/reactos/lib/kernel32/thread/fiber.c
+++ b/reactos/lib/kernel32/thread/fiber.c
@@ -235,6 +235,17 @@ DeleteFiber(LPVOID lpFiber)
                         MEM_RELEASE);
 }
 
+/*
+ * @implemented
+ */
+BOOL
+WINAPI
+IsThreadAFiber(VOID)
+{
+    return NtCurrentTeb()->HasFiberData;
+}
+
+
 __declspec(noreturn)
 VOID
 WINAPI