Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x13 inch pan.
In a medium bowl, stir together the cake mix and instant pudding. Then continue to prepare cake mix as directed on box. Pour into the prepared pan.
Bake cake as directed on package. When the cake comes out of the oven, poke holes all over the top of the cake with a toothpick.
In a medium bowl, stir together the confectioners' sugar, lemon juice and melted butter until smooth. Pour the icing over the hot cake, and allow to cool before serving.
