diff --git a/heartbeat.module b/heartbeat.module
index 272e9a0..6f48727 100755
--- a/heartbeat.module
+++ b/heartbeat.module
@@ -679,7 +679,7 @@ class HeartbeatMessagePool {
   /**
    * getInstance().
    */
-  public function getInstance() {
+  public static function getInstance() {
     if (!isset(self::$instance)) {
       self::$instance = new HeartbeatMessagePool();
     }