Rambling post about Kings below, I'm a little tired so twice the ramble
If he had AQ, AK, QQ or JJ which some people will come over the top with like that but not call all in, you haven't given him a chance to make a further mistake on the flop which will likely not help either of you.
AA can have my KK's money there is so few times I'm shown AA compared to AQ that I'm willing to gamble it up against all but super rocks, but I would rather do my gambling after looking at the flop against most of my current opponents. For the most part super rocks don't exist in the games I've been playing, but a type of player that makes KK closer to value to QQ-99 preflop and much stronger after seeing the first three cards Ace free. I know that sounds horribly weak tight and doesn't really help you in this situation as you would still lose a stack on most flops, but it has cut down on my variance a lot, as I can better make up my mind especially with position as to the strength of their hand. AQ and smaller pairs will still often play way too hard after all the action they have given up preflop even when they miss, but it gives me a chance to dodge the 3 cards that make me sick to see on the flop.
So it is mostly opponent dependant on how hard I play KK preflop, some people I move in as they will call with a ton of pairs I beat, but not Ax, others I play it like a small pair preflop and KK post flop, and the other more rare super rock smooth call and pray for a set.