diff --git a/source/campaigns/editor/filters.rst b/source/campaigns/editor/filters.rst
index d68b298fe..d3a9d26cb 100644
--- a/source/campaigns/editor/filters.rst
+++ b/source/campaigns/editor/filters.rst
@@ -955,6 +955,28 @@ Available options:
 
 |hr|
 
+prepend\_to\_array
+..................
+
+Prepends elements to an existing array.
+
+Liquid
+
+.. code-block:: liquid
+
+   {% assign my_array = "" | new_array: "element1", "element2" %}
+   {% assign my_array = my_array | prepend_to_array: "element3" %}
+
+   Array: {{ my_array | json }}
+
+Rendered Liquid
+
+.. code-block:: text
+
+   Array: ["element3","element1","element2"]
+
+|hr|
+
 probability\_by
 ...............