diff --git a/src/mscorlib/src/System/Threading/ThreadPool.cs b/src/mscorlib/src/System/Threading/ThreadPool.cs
index 34810674ece2..fcf40a0241f1 100644
--- a/src/mscorlib/src/System/Threading/ThreadPool.cs
+++ b/src/mscorlib/src/System/Threading/ThreadPool.cs
@@ -1443,6 +1443,8 @@ internal _ThreadPoolWaitOrTimerCallback(WaitOrTimerCallback waitOrTimerCallback,
         [System.Security.SecurityCritical]  // auto-generated
         static internal void PerformWaitOrTimerCallback(Object state, bool timedOut)
         {
+            ThreadPool.EnsureVMInitialized();
+
             _ThreadPoolWaitOrTimerCallback helper = (_ThreadPoolWaitOrTimerCallback)state; 
             Contract.Assert(helper != null, "Null state passed to PerformWaitOrTimerCallback!");
             // call directly if it is an unsafe call OR EC flow is suppressed
@@ -1928,7 +1930,7 @@ unsafe public static bool UnsafeQueueNativeOverlapped(NativeOverlapped* overlapp
 
         [SecurityCritical]
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        private static void EnsureVMInitialized()
+        internal static void EnsureVMInitialized()
         {
             if (!ThreadPoolGlobals.vmTpInitialized)
             {