diff --git a/activerecord/lib/active_record/associations/association_collection.rb b/activerecord/lib/active_record/associations/association_collection.rb
index 09a80be266..b7f37e53f7 100644
--- a/activerecord/lib/active_record/associations/association_collection.rb
+++ b/activerecord/lib/active_record/associations/association_collection.rb
@@ -320,8 +320,8 @@ module ActiveRecord
         exists?(record)
       end
 
-      def proxy_respond_to?(method)
-        super || @reflection.klass.respond_to?(method)
+      def proxy_respond_to?(method, include_private = false)
+        super || @reflection.klass.respond_to?(method, include_private)
       end
 
       protected
diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
index dada2d1603..8d97b30c74 100644
--- a/activerecord/test/cases/associations/has_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -1081,8 +1081,14 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
   end
 
   def test_sending_new_to_association_proxy_should_have_same_effect_as_calling_new
-    clients_assoc = companies(:first_firm).clients
-    assert_equal clients_assoc.new.attributes, clients_assoc.send(:new).attributes
+    client_association = companies(:first_firm).clients
+    assert_equal client_association.new.attributes, client_association.send(:new).attributes
+  end
+
+  def test_respond_to_private_class_methods
+    client_association = companies(:first_firm).clients
+    assert !client_association.respond_to?(:private_method)
+    assert client_association.respond_to?(:private_method, true)
   end
 end
 
diff --git a/activerecord/test/models/company.rb b/activerecord/test/models/company.rb
index 62d20861f3..0e3fafa37c 100644
--- a/activerecord/test/models/company.rb
+++ b/activerecord/test/models/company.rb
@@ -112,6 +112,14 @@ class Client < Company
   def rating?
     query_attribute :rating
   end
+
+  class << self
+    private
+
+    def private_method
+      "darkness"
+    end
+  end
 end