diff --git a/lib/rake/phony.rb b/lib/rake/phony.rb
index eb7e9f2b0..29633ae06 100644
--- a/lib/rake/phony.rb
+++ b/lib/rake/phony.rb
@@ -8,6 +8,8 @@
 
 task :phony
 
-def (Rake::Task[:phony]).timestamp # :nodoc:
-  Time.at 0
+Rake::Task[:phony].tap do |task|
+  def task.timestamp # :nodoc:
+    Time.at 0
+  end
 end