Grease the bundt pan and preheat the oven to 325 degrees. Add the box of cake mix, pudding, water, eggs, and oil to a large bowl. Using a hand mixer, beat on medium speed for 2 minutes.
Pour batter into the prepared baking pan and bake for 45-50 minutes. Cool for 15 minutes, then transfer to a cooling rack to finish.
Whisk together the powdered sugar and lemon juice in a small bowl.
Add the milk a little at a time until the desired consistency is reached.
Transfer the cake to a serving plate and drizzle the glaze over the top of the cake. Top with lemon zest.