diff --git a/lib/definitions/redefiner.rb b/lib/definitions/redefiner.rb
index 4b4a79f..9d721f1 100644
--- a/lib/definitions/redefiner.rb
+++ b/lib/definitions/redefiner.rb
@@ -27,11 +27,11 @@ module Low
   class Redefiner
     class << self
       # TODO: Pass in "klass" and use it to class_eval/eval methods in the binding of the class that included LowType.
-      def redefine(method_proxies:, class_proxy:)
+      def redefine(method_proxies:, class_proxy:, klass: nil)
         if LowType.config.type_checking
           typed_methods(method_proxies:, class_proxy:)
         else
-          untyped_methods(method_proxies:, class_proxy:)
+          rewrite_methods(method_proxies:, class_proxy:, klass:)
         end
       end
 
@@ -52,6 +52,20 @@ def untyped_args(args:, kwargs:, method_proxy:) # rubocop:disable Metrics/AbcSiz
 
       private
 
+      def rewrite_methods(method_proxies:, class_proxy:, klass:)
+        method_proxies.values.filter(&:expressions?).each do |method_proxy|
+          method_proxy.rewrite_signature
+
+          klass.class_eval(method_proxy.export, method_proxy.file_path, method_proxy.start_line)
+
+          if class_proxy.private_start_line && method_proxy.start_line > class_proxy.private_start_line
+            klass.send(:private, method_proxy.name)
+          end
+        end
+
+        nil
+      end
+
       def typed_methods(method_proxies:, class_proxy:) # rubocop:disable Metrics
         Module.new do
           method_proxies.values.filter(&:expressions?).each do |method_proxy|
diff --git a/lib/low_type.rb b/lib/low_type.rb
index 304d430..4c98dbd 100644
--- a/lib/low_type.rb
+++ b/lib/low_type.rb
@@ -52,8 +52,11 @@ def self.included(klass)
 
       Low::Evaluator.evaluate(method_proxies: class_proxy.keyed_methods, class_binding: class_proxy.class_binding)
 
-      klass.prepend Low::Redefiner.redefine(method_proxies: class_proxy.instance_methods, class_proxy:)
-      klass.singleton_class.prepend Low::Redefiner.redefine(method_proxies: class_proxy.class_methods, class_proxy:)
+      result = Low::Redefiner.redefine(method_proxies: class_proxy.instance_methods, class_proxy:, klass:)
+      klass.prepend result if result
+
+      singleton_result = Low::Redefiner.redefine(method_proxies: class_proxy.class_methods, class_proxy:, klass: klass.singleton_class)
+      klass.singleton_class.prepend singleton_result if singleton_result
 
       Low::Adapter::Loader.load(klass:, class_proxy:)