diff --git a/lib/adamantium/gently_remind_me.rb b/lib/adamantium/gently_remind_me.rb
index 8a5e257..3fe1e36 100644
--- a/lib/adamantium/gently_remind_me.rb
+++ b/lib/adamantium/gently_remind_me.rb
@@ -1,3 +1,5 @@
+require "mail"
+
 module Adamantium
   class GentlyRemindMe
     def call(limit:)