diff --git a/lib/celluloid/actor.rb b/lib/celluloid/actor.rb
index <HASH>..<HASH> 100644
--- a/lib/celluloid/actor.rb
+++ b/lib/celluloid/actor.rb
@@ -371,7 +371,7 @@ module Celluloid
 
     # Run a method inside a task unless it's exclusive
     def task(task_type, method_name = nil, &block)
-      if @exclusives && method_name && (@exclusives == :all || @exclusives.include?(method_name))
+      if @exclusives && (@exclusives == :all || @exclusives.include?(method_name))
         exclusive { block.call }
       else
         @task_class.new(:message_handler, &block).resume
Fix operation in exclusive :all mode