Sugarless Pumpkin Pie

1 (9-inch) baked pie shell
2 small boxes sugar-free instant vanilla pudding
2 cups milk
2 cups plain canned pumpkin (not pumpkin pie mixture)
1/4 teaspoon nutmeg
1/4 teaspoon ginger
1/2 teaspoon cinnamon

Blend all ingredients in blender until smooth. Pour into baked pie shell and chill until ready to use.