Grease and flour a bundt pan. In a large bowl, combine dry cake mix, cubed wate rmelon, gelatin powder, egg whites and oil. Beat until smooth. Pour into a prep ared pan and bake at 350 degrees for about 35 minutes or until cake tester inse rted in cake comes out clean. Cool on a rack and frost with watermelon icing.
Icing: Beat cream cheese and butter until fluffy. Add sugar and watermelon juic e; stir until blended.