diff --git src/bp-templates/bp-nouveau/includes/messages/ajax.php src/bp-templates/bp-nouveau/includes/messages/ajax.php
index c66c40ba6..c7bf9ab02 100644
--- src/bp-templates/bp-nouveau/includes/messages/ajax.php
+++ src/bp-templates/bp-nouveau/includes/messages/ajax.php
@@ -207,6 +207,9 @@ function bp_nouveau_ajax_get_user_message_threads() {
 	if ( isset( $_POST['box'] ) && 'starred' === $_POST['box'] ) {
 		$star_filter = true;
 
+		// Include the file containing the filter
+		require buddypress()->messages->path . 'bp-messages/screens/starred.php';
+
 		// Add the message thread filter.
 		add_filter( 'bp_after_has_message_threads_parse_args', 'bp_messages_filter_starred_message_threads' );
 	}