Preheat oven to 350°F. Spray star pan with vegetable pan spray. In large bowl, beat cake mix, water, oil, eggs and berry gelatin with electric mixer 30 seconds. Increase speed to medium; beat 2 minutes. Pour into prepared pan. Bake 32-35 minutes or until toothpick inserted in center comes out clean. Cool cake in pan 10 minutes. Remove cake from pan and cool completely.
Prepare icing mix according to package directions. Place cake onto serving plate. Spatula ice cake smooth with icing.
Position sliced strawberries. Pipe 3-4 rows of tip 21 stars in shape of a star on cake top. Fill center of icing star with blueberries. Add tip 21 star bottom border.