Yield: 12 servings - 4 points per serving
Preheat oven according to the temperature on the cake box.
Add the cake mix and Sprite Zero to a large mixing bowl. Use a handheld mixer to beat together (medium speed) for 2 minutes.
Spray two 8 inch cake pans with no-stick cooking spray. Evenly divide the cake batter, then bake 28-30 minutes, or until a toothpick inserted in the middle comes out clean.
While the cake is baking chop the strawberries.
Let cakes cool completely, then remove cakes from pan.
Spread half of the Cool Whip over the top of one cake. Then add half of the strawberries and half of the blueberries.
Place the second cake on top of the first cake. Cover the top of the second cake with the remaining Cool Whip, strawberries and blueberries. Enjoy!