diff --git a/lib/active_model/serializer/generators/serializer/serializer_generator.rb b/lib/active_model/serializer/generators/serializer/serializer_generator.rb
index 7c4c036d..40a8f939 100644
--- a/lib/active_model/serializer/generators/serializer/serializer_generator.rb
+++ b/lib/active_model/serializer/generators/serializer/serializer_generator.rb
@@ -26,7 +26,7 @@ module Rails
         if options[:parent]
           options[:parent]
         elsif (ns = Rails::Generators.namespace) && ns.const_defined?(:ApplicationSerializer) ||
-               defined?(::ApplicationSerializer)
+               (Object.const_get(:ApplicationSerializer) rescue nil)
           'ApplicationSerializer'
         else
           'ActiveModel::Serializer'