diff --git a/wp-includes/class-wp-theme.php b/wp-includes/class-wp-theme.php
index f9f93994e7..a8975457d2 100644
--- a/wp-includes/class-wp-theme.php
+++ b/wp-includes/class-wp-theme.php
@@ -242,6 +242,9 @@ final class WP_Theme implements ArrayAccess {
 			}
 		}
 
+		// Handle a numeric theme directory as a string.
+		$theme_dir = (string) $theme_dir;
+
 		$this->theme_root = $theme_root;
 		$this->stylesheet = $theme_dir;
 
diff --git a/wp-includes/version.php b/wp-includes/version.php
index eeea9e5588..8adcbf1ab3 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -16,7 +16,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '6.2-beta3-55425';
+$wp_version = '6.2-beta3-55426';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.