Preheat oven to 180°C/350°F/Gas 4 and spray a 9-inch round bundt pan with non-stick baking spray.
Using an electric handheld or standing mixer, beat the cake mix, instant pudding, sour cream, eggs, oil, lemon juice, and water until combined.
Fold in the fresh blueberries.
Pour the cake batter into the bundt pan and bake in the oven for 45-55 minutes or until an inserted toothpick comes out clean.
Leave to cool in the pan for 10-15 minutes, before transferring to a wire rack to cool completely. Place in the refrigerator overnight before frosting.
To make the cream cheese frosting, use an electric handheld or standing mixer and beat all of the frosting ingredients except the lemon zest, until combined and smooth.
Place cake on serving plate and pour the frosting on top.
Zest the lemon over the cake to decorate, and add extra blueberries too, if desired. Enjoy!