diff --git a/CHANGES.txt b/CHANGES.txt
index e77e101..c83a9d5 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -4,6 +4,10 @@ Changelog
 2.2.1 (unreleased)
 ------------------
 
+- Make conversation view not break when comment-id cannot be converted to long.
+  Fixes #13327
+  [khink]
+
 - fix insufficient privileges when trying to view
   the RSS feed of a comment collection
   [maartenkling]
diff --git a/plone/app/discussion/conversation.py b/plone/app/discussion/conversation.py
index 2d870fe..ec2520c 100644
--- a/plone/app/discussion/conversation.py
+++ b/plone/app/discussion/conversation.py
@@ -210,7 +210,11 @@ class Conversation(Traversable, Persistent, Explicit):
     def __getitem__(self, key):
         """Get an item by its long key
         """
-        return self._comments[long(key)].__of__(self)
+        try:
+            comment_id = long(key)
+        except ValueError:
+            return
+        return self._comments[comment_id].__of__(self)
 
     def __delitem__(self, key, suppress_container_modified=False):
         """Delete an item by its long key
diff --git a/plone/app/discussion/tests/test_conversation.py b/plone/app/discussion/tests/test_conversation.py
index 76babf9..a424a28 100644
--- a/plone/app/discussion/tests/test_conversation.py
+++ b/plone/app/discussion/tests/test_conversation.py
@@ -699,6 +699,14 @@ class ConversationTest(unittest.TestCase):
         self.assertEqual('http://nohost/plone/doc1/++conversation++default',
                           conversation.absolute_url())
 
+    def test_unconvertible_id(self):
+        # make sure the conversation view doesn't break when given comment id
+        # can't be converted to long
+
+        conversation = self.portal.doc1.restrictedTraverse(
+            '++conversation++default/ThisCantBeRight')
+        self.assertEqual(conversation, None)
+
     def test_parent(self):
         # Check that conversation has a content object as parent
 
diff --git a/plone/app/discussion/tests/test_functional.py b/plone/app/discussion/tests/test_functional.py
index 25730b0..0c7f31e 100644
--- a/plone/app/discussion/tests/test_functional.py
+++ b/plone/app/discussion/tests/test_functional.py
@@ -20,7 +20,7 @@ optionflags = (
     doctest.REPORT_ONLY_FIRST_FAILURE)
 normal_testfiles = [
     'functional_test_comments.txt',
-    'functional_test_comment_review_workflow.txt'
+    'functional_test_comment_review_workflow.txt',
 ]