diff --git a/mozilla/nsprpub/pr/src/threads/prcmon.c b/mozilla/nsprpub/pr/src/threads/prcmon.c
index 138e2083643..3166fc5b60e 100644
--- a/mozilla/nsprpub/pr/src/threads/prcmon.c
+++ b/mozilla/nsprpub/pr/src/threads/prcmon.c
@@ -303,6 +303,8 @@ PR_IMPLEMENT(PRMonitor*) PR_CEnterMonitor(void *address)
 {
     PRMonitor *mon;
 
+    if (!_pr_initialized) _PR_ImplicitInitialization();
+
     _PR_LOCK_MCACHE();
     mon = CreateMonitor(address);
     _PR_UNLOCK_MCACHE();