Crockpot Egg Noodle Lasagna

1 (8 ounce) bag wide egg noodles
3 tablespoons butter
1 1/2 pounds ground beef
2 1/4 cups spaghetti sauce
6 ounces Velveeta cheese, cubed
3 cups (12 ounces) shredded mozzarella cheese

Cook noodles. Add butter and toss to coat. Brown beef in skillet and drain. Spread 1/4 of spaghetti sauce in crockpot. Layer with 1/3 noodles, 1/3 beef, 1/3 of remaining sauce, and 1/3 both the cheeses. Repeat layers twice. Cook on LOW for 4 hours until cheeses are melted and lasagna is heated through.