Cook the fries according to the package directions - usually about 12-15 minutes in a preheated hot oven (Mk 7 - 425ºF - 220ºC). Meanwhile, shred the mozzarella and thinly slice the pepperoni.
When the fries are browned, remove the dish from the oven and pour the pizza sauce over the fries. Top with the cheese and pepperoni and bake for a further 5 minutes or until the sauce is warm and the cheese has melted. Apply to face immediately.