diff --git a/lib/ostruct.rb b/lib/ostruct.rb
index a8763da..ecf37a9 100644
--- a/lib/ostruct.rb
+++ b/lib/ostruct.rb
@@ -252,12 +252,13 @@ def new_ostruct_member!(name) # :nodoc:
   private :new_ostruct_member!
 
   private def is_method_protected!(name) # :nodoc:
-    if !respond_to?(name, true)
+    sc = singleton_class!
+    if !(sc.method_defined?(name) || sc.private_method_defined?(name))
       false
     elsif name.match?(/!$/)
       true
     else
-      owner = method!(name).owner
+      owner = sc.instance_method(name).owner
       if owner.class == ::Class
         owner < ::OpenStruct
       else
diff --git a/test/ostruct/test_ostruct.rb b/test/ostruct/test_ostruct.rb
index 616f84d..f0cbd7d 100644
--- a/test/ostruct/test_ostruct.rb
+++ b/test/ostruct/test_ostruct.rb
@@ -439,4 +439,10 @@ def test_performance_warning
       )
     end
   end
+  def test_initialize_with_respond_to_field
+    o = OpenStruct.new(respond_to?: false, next_field: 3)
+
+    assert_equal({respond_to?: false, next_field: 3}, o.to_h)
+  end
+
 end