Pumpkin Mousse Pie

1 package (4-serving size) vanilla flavor instant pudding and pie filling
3/4 cup cold milk
1/2 cup solid-pack pumpkin
3/4 teaspoon pumpkin pie spice
3 1/2 cups Cool Whip, thawed
1 baked 9-inch pie shell, cooled

Prepare pie filling mix as directed on package with 3/4 cup milk. Blend in pumpkin, pumpkin pie spice and 2 cups whipped topping. Spoon into pie shell. Chill at least 4 hours. Spread with remaining whipped topping.