diff --git a/js/xpconnect/src/XPCWrappedJS.cpp b/js/xpconnect/src/XPCWrappedJS.cpp
index 866e0a9920ac..637cfb6fe4d4 100644
--- a/js/xpconnect/src/XPCWrappedJS.cpp
+++ b/js/xpconnect/src/XPCWrappedJS.cpp
@@ -11,7 +11,6 @@
 #include "nsProxyRelease.h"
 #include "nsThreadUtils.h"
 #include "nsTextFormatter.h"
-#include "nsCycleCollectorUtils.h"
 
 // NOTE: much of the fancy footwork is done in xpcstubs.cpp
 
@@ -151,8 +150,6 @@ nsXPCWrappedJS::QueryInterface(REFNSIID aIID, void** aInstancePtr)
 nsrefcnt
 nsXPCWrappedJS::AddRef(void)
 {
-    if (!MOZ_LIKELY(NS_IsMainThread() || NS_IsCycleCollectorThread()))
-        MOZ_CRASH();
     nsrefcnt cnt = NS_AtomicIncrementRefcnt(mRefCnt);
     NS_LOG_ADDREF(this, cnt, "nsXPCWrappedJS", sizeof(*this));
 
@@ -167,8 +164,6 @@ nsXPCWrappedJS::AddRef(void)
 nsrefcnt
 nsXPCWrappedJS::Release(void)
 {
-    if (!MOZ_LIKELY(NS_IsMainThread() || NS_IsCycleCollectorThread()))
-        MOZ_CRASH();
     NS_PRECONDITION(0 != mRefCnt, "dup release");
 
     if (mMainThreadOnly && !NS_IsMainThread()) {
@@ -282,10 +277,6 @@ nsXPCWrappedJS::GetNewOrUsed(JSContext* cx,
                              nsISupports* aOuter,
                              nsXPCWrappedJS** wrapperResult)
 {
-    // Do a release-mode assert against accessing nsXPCWrappedJS off-main-thread.
-    if (!MOZ_LIKELY(NS_IsMainThread() || NS_IsCycleCollectorThread()))
-        MOZ_CRASH();
-
     JS::RootedObject jsObj(cx, aJSObj);
     JSObject2WrappedJSMap* map;
     nsXPCWrappedJS* root = nullptr;
@@ -568,10 +559,6 @@ nsXPCWrappedJS::CallMethod(uint16_t methodIndex,
                            const XPTMethodDescriptor* info,
                            nsXPTCMiniVariant* params)
 {
-    // Do a release-mode assert against accessing nsXPCWrappedJS off-main-thread.
-    if (!MOZ_LIKELY(NS_IsMainThread() || NS_IsCycleCollectorThread()))
-        MOZ_CRASH();
-
     if (!IsValid())
         return NS_ERROR_UNEXPECTED;
     if (NS_IsMainThread() != mMainThread) {
diff --git a/js/xpconnect/tests/unit/test_bug608142.js b/js/xpconnect/tests/unit/test_bug608142.js
new file mode 100644
index 000000000000..6eb938760fd3
--- /dev/null
+++ b/js/xpconnect/tests/unit/test_bug608142.js
@@ -0,0 +1,35 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
+ * vim: sw=4 ts=4 sts=4 et
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+function run_test() { 
+    var tm = Components.classes["@mozilla.org/thread-manager;1"].getService();
+    var thr = tm.newThread(0);
+
+    var foundThreadError = false;
+ 
+    var listener = {
+        observe: function(message) {
+            if (/JS function on a different thread/.test(message.message))
+                foundThreadError = true;
+        }
+    };
+
+    var cs = Components.classes["@mozilla.org/consoleservice;1"].
+        getService(Components.interfaces.nsIConsoleService);
+    cs.registerListener(listener);
+
+    thr.dispatch({
+        run: function() {
+            do_check_true(false);
+        }
+    }, Components.interfaces.nsIThread.DISPATCH_NORMAL);
+
+    thr.shutdown();
+
+    cs.unregisterListener(listener);
+    do_check_true(foundThreadError);
+}
+
diff --git a/js/xpconnect/tests/unit/xpcshell.ini b/js/xpconnect/tests/unit/xpcshell.ini
index 1889a5b55046..3db8ba3d330b 100644
--- a/js/xpconnect/tests/unit/xpcshell.ini
+++ b/js/xpconnect/tests/unit/xpcshell.ini
@@ -7,6 +7,7 @@ tail =
 [test_bug451678.js]
 [test_bug596580.js]
 [test_bug604362.js]
+[test_bug608142.js]
 [test_bug641378.js]
 [test_bug677864.js]
 [test_bug711404.js]