Well, wouldn't surprise me, it's Africa after all, and it's not impossible that the various civilizations at least kept in touch. One or two adventurous Egyptians must have travelled south of Nubia at least once, and vice versa.
Although what is surprising in the case of king Tut is that, well... The Egyptian pharaoes hadn't exactly figured out the whole interbreeding thing. That is, they were more concerned about their bloodline being potentially thinned out than with making sure they had functional babies. Seems there were some fresh blood introduced at some point atleast, then.
