Pepperoni Baked Spagetti

I make several kinds of spaghetti and baked spaghetti because it is always a family favorite.  This is one similar to a local cafeteria here called K&W. 

1 jar PREGO spaghetti sauce (flavor of choice)
1 small box spaghetti (I always use thin spaghetti)
package sliced pepperoni
1 pack shredded cheddar and 1 pack mozzarella cheese

Cook and drain spaghetti.  Mix noodles with sauce and pour in pan.  Top with pepperoni and cheeses.  Sprinkle with parmesan if desired.