diff --git a/wp-includes/post-template.php b/wp-includes/post-template.php
index ac8864334a..701af8de4a 100644
--- a/wp-includes/post-template.php
+++ b/wp-includes/post-template.php
@@ -1631,6 +1631,10 @@ function get_the_password_form( $post = 0 ) {
  * @return bool True on success, false on failure.
  */
 function is_page_template( $template = '' ) {
+	if ( ! is_singular() ) {
+		return false;
+	}
+
 	$page_template = get_page_template_slug( get_queried_object_id() );
 
 	if ( empty( $template ) )
diff --git a/wp-includes/version.php b/wp-includes/version.php
index f4807a6266..41e8fc2a18 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '4.8-alpha-39598';
+$wp_version = '4.8-alpha-39599';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.