diff --git a/ipykernel/kernelbase.py b/ipykernel/kernelbase.py
index 4fe10ffdd..bae127d49 100644
--- a/ipykernel/kernelbase.py
+++ b/ipykernel/kernelbase.py
@@ -171,7 +171,7 @@ def post_fork_callback(pid, conn):
             metadata = {}
             metadata = self.finish_metadata(parent, metadata, reply_content)
 
-            self.session.send(stream, u'execute_reply',
+            self.session.send(stream, u'fork_reply',
                                         reply_content, parent, metadata=metadata,
                                         ident=ident)
 
diff --git a/ipykernel/tests/test_kernel.py b/ipykernel/tests/test_kernel.py
index 7560bcddb..c776b46f5 100644
--- a/ipykernel/tests/test_kernel.py
+++ b/ipykernel/tests/test_kernel.py
@@ -333,7 +333,7 @@ def test_fork_metadata():
         km = kc.parent
         fork_msg_id = kc.fork()
         fork_reply = kc.get_shell_msg(block=True, timeout=TIMEOUT)
-        # validate_message(fork_reply, "execute_reply", fork_msg_id)  # TODO: Make it work (need the `fork_reply`)
+        validate_message(fork_reply, "fork_reply", fork_msg_id)
         assert fork_msg_id == fork_reply['parent_header']['msg_id'] == fork_msg_id
         assert fork_reply['content']['conn']['key'] != kc.session.key.decode()
         fork_pid = fork_reply['content']['pid']
diff --git a/ipykernel/tests/test_message_spec.py b/ipykernel/tests/test_message_spec.py
index e75e219c6..fd04399e8 100644
--- a/ipykernel/tests/test_message_spec.py
+++ b/ipykernel/tests/test_message_spec.py
@@ -195,6 +195,11 @@ class IsCompleteReplyIncomplete(Reference):
     indent = Unicode()
 
 
+class ForkReply(Reply):
+    pid = Integer()
+    conn = Dict()
+
+
 # IOPub messages
 
 class ExecuteInput(Reference):
@@ -240,6 +245,7 @@ class HistoryReply(Reply):
     'stream' : Stream(),
     'display_data' : DisplayData(),
     'header' : RHeader(),
+    'fork_reply' : ForkReply(),
 }
 """
 Specifications of `content` part of the reply messages.