diff --git a/lib/twine/plugin.rb b/lib/twine/plugin.rb
index 0967e1ad..c6962235 100644
--- a/lib/twine/plugin.rb
+++ b/lib/twine/plugin.rb
@@ -1,3 +1,4 @@
+require 'date'
 require 'safe_yaml/load'
 
 SafeYAML::OPTIONS[:suppress_warnings] = true