Can I take two different protein shakes at the same time?

I'm about to order a pot of "Reflex-creatine creapure" and "prolab n large 2" and was thinking of using them both after workouts. I'm 20, pretty slim and looking to gain a serious amount of weight for summer. These two products are consistantly voted amongst the best in the world, and have been recommended by the worlds leading creatine researchers, but will taking them at the same time be harmful?