diff --git a/lib/forwardable.rb b/lib/forwardable.rb
index 449c344..ee0038d 100644
--- a/lib/forwardable.rb
+++ b/lib/forwardable.rb
@@ -148,9 +148,8 @@ def instance_delegate(hash)
   #   def_delegator :@records, :map
   #
   def def_instance_delegators(accessor, *methods)
-    methods.delete("__send__")
-    methods.delete("__id__")
-    for method in methods
+    methods.each do |method|
+      next if /\A__(?:send|id)__\z/ =~ method
       def_instance_delegator(accessor, method)
     end
   end
@@ -280,9 +279,8 @@ def single_delegate(hash)
   #   def_delegator :@records, :map
   #
   def def_single_delegators(accessor, *methods)
-    methods.delete("__send__")
-    methods.delete("__id__")
-    for method in methods
+    methods.each do |method|
+      next if /\A__(?:send|id)__\z/ =~ method
       def_single_delegator(accessor, method)
     end
   end
diff --git a/test/test_forwardable.rb b/test/test_forwardable.rb
index b3f8467..9101eff 100644
--- a/test/test_forwardable.rb
+++ b/test/test_forwardable.rb
@@ -96,6 +96,18 @@ def test_def_instance_delegators_using_block_method_as_receiver
     end
   end
 
+  def test_def_instance_delegators_send_id
+    %i[def_delegators def_instance_delegators].each do |m|
+      cls = forwardable_class do
+        attr_reader :receiver
+        __send__ m, :@receiver, :__send__, :__id__
+      end
+
+      assert_not_equal cls.new.__id__, cls.new.receiver.__id__
+      assert_not_equal cls.new.__send__(:__id__), cls.new.receiver.__send__(:__id__)
+    end
+  end
+
   def test_instance_delegate
     %i[delegate instance_delegate].each do |m|
       cls = forwardable_class do
@@ -204,6 +216,18 @@ def test_obj_single_delegators
     end
   end
 
+  def test_obj_single_delegators_send_id
+    %i[def_delegators def_single_delegators].each do |m|
+      obj = single_forwardable_object do
+        singleton_class.attr_reader :receiver
+        __send__ m, :@receiver, :__send__, :__id__
+      end
+
+      assert_not_equal obj.__id__, obj.receiver.__id__
+      assert_not_equal obj.__send__(:__id__), obj.receiver.__send__(:__id__)
+    end
+  end
+
   def test_obj_single_delegate
     %i[delegate single_delegate].each do |m|
       obj = single_forwardable_object do