4 large white potatoes, peeled, chopped and cooked
4 large sweet potatoes, peeled, chopped and cooked
1 (250 g) tub PHILADELPHIA Chive & Onion Cream Cheese Product, divided
1/2 cup sour cream, divided
1/4 teaspoon salt
1/4 teaspoon black pepper
1/4 cup KRAFT 100% Parmesan Finely Shredded Cheese
1/4 cup KRAFT Double Cheddar Shredded Cheese, divided