diff --git a/activesupport/lib/active_support/multibyte/chars.rb b/activesupport/lib/active_support/multibyte/chars.rb
index 60f082bcc1..96ed35f0e0 100644
--- a/activesupport/lib/active_support/multibyte/chars.rb
+++ b/activesupport/lib/active_support/multibyte/chars.rb
@@ -1,4 +1,5 @@
 # encoding: utf-8
+require 'active_support/core_ext/string/behavior'
 
 module ActiveSupport #:nodoc:
   module Multibyte #:nodoc: