diff --git a/src/main/java/com/rabbitmq/client/impl/AMQConnection.java b/src/main/java/com/rabbitmq/client/impl/AMQConnection.java
index dfaa8989e..6eb181c6a 100644
--- a/src/main/java/com/rabbitmq/client/impl/AMQConnection.java
+++ b/src/main/java/com/rabbitmq/client/impl/AMQConnection.java
@@ -321,6 +321,10 @@ public void start()
         // initiator) is to wait for a connection.start method to
         // arrive.
         _channel0.enqueueRpc(connStartBlocker);
+        // Must happen before the header is sent: sending it can make the broker reply
+        // immediately, and the I/O thread that reads that reply needs the connection
+        // reference to already be in place, or it hits a null reference.
+        this._frameHandler.initialize(this);
         try {
             // The following two lines are akin to AMQChannel's
             // transmit() method for this pseudo-RPC.
@@ -331,8 +335,6 @@ public void start()
             throw ioe;
         }
 
-        this._frameHandler.initialize(this);
-
         AMQP.Connection.Start connStart;
         AMQP.Connection.Tune connTune = null;
         try {