"Don't know about you, but I've nearly managed that now." He did, in fact, know how old Arthur was, but he still wasn't entirely sure if he was supposed to, since most people assumed Arthur was older than he actually was, and Eames wasn't the sort of person who would out a friend that way.

The statement wasn't as much of a joke as he was trying for, and he knew just how short of the mark it had fallen, shaking his head a moment later, "Oughtn't joke about it, I suppose. Though I don't know if I can really help it."