Cook bacon in a skillet until crisp; drain, reserving 2 tablespoons drippings in pan. Crumble bacon, and set aside.
Add onion and bell pepper to drippings; sauté 2 minutes or until tender. Stir in milk, soup, and cheese; cook, stirring constantly, until blended. Stir in turkey, spaghetti, and pimiento. Spoon into a lightly greased 2-quart baking dish.
Bake at 375° for 30 minutes or until thoroughly heated. Sprinkle with reserved bacon.