3 cups medium noodles, uncooked
1 {6 1/2 oz.} can tuna, drained and flaked
1 cup sliced celery
1/2 mayonnaise
1/3 cup chopped onion
1/4 cup chopped green bell pepper
1 can condensed cream of celery or cream of mushroom soup
1/2 cup milk
1 cup shredded Cheddar cheese

Cook the noodles according to package directions; drain and set aside.
Preheat oven to 425 degrees. In a large bowl, stir together noodles, tuna, celery, mayonnaise or salad dressing, onion, green pepper; set aside.
In a medium saucepan, stir together the undiluted soup and milk; heat through. Add the cheese; cook and stir the mixture until the cheese melts.
Add the soup mixture to the noodle mixture and gently stir to mix all of the ingredients together.
Spoon the tuna-noodle mixture into a 2-qt. casserole dish. Cover and bake in the 425 degree oven for 20 minutes, or until the casserole is heated through.