diff --git a/reference/forms/types/collection.rst b/reference/forms/types/collection.rst
index c9e237181b3..28d0fce9422 100644
--- a/reference/forms/types/collection.rst
+++ b/reference/forms/types/collection.rst
@@ -20,6 +20,7 @@ photos).
 |             | - `entry_options`_                                                          |
 |             | - `entry_type`_                                                             |
 |             | - `prototype`_                                                              |
+|             | - `prototype_data`_                                                         |
 |             | - `prototype_name`_                                                         |
 +-------------+-----------------------------------------------------------------------------+
 | Inherited   | - `by_reference`_                                                           |
@@ -363,6 +364,31 @@ rendering your form, having the entire "form row" may be easier for you.
 For details on how to actually use this option, see the above example as
 well as :ref:`cookbook-form-collections-new-prototype`.
 
+prototype_data
+~~~~~~~~~~~~~~
+
+.. versionadded:: 2.8
+    The ``prototype_data`` option was introduced in Symfony 2.8.
+
+**type**: ``mixed`` **default**: ``null``
+
+Allows you to define specific data for the prototype. Each new row added will
+initially contain the data set by this option. By default, the data configured
+for all entries with the ``entry_options`` option will be used.
+
+.. code-block:: php
+
+    use Symfony\Component\Form\Extension\Core\Type\CollectionType;
+    use Symfony\Component\Form\Extension\Core\Type\TextType;
+    // ...
+
+    $builder->add('tags', CollectionType::class, array(
+        'entry_type' => TextType::class,
+        'allow_add' => true,
+        'prototype' => true,
+        'prototype_data' => 'New Tag Placeholder',
+    ));
+
 prototype_name
 ~~~~~~~~~~~~~~