I have this trans guy friend in real life (I'll call him T#) - I wouldn't say we're close, but I've known him since 2003 and we bump into each other usually two or three times a year at sci-fi/comic/zine conventions and the like. I knew him pre-transition and did know he was struggling with gender identity - when I first saw him after he started HRT the first thing he said to me was "Look! I have a beard!", and indeed he did!! That was five or six years ago now.
Because I was conflicted about my own trans history I never told him about my earlier attempt at transition and was happy to be seen by him as an Ally. I'm close friends with a mutual friend of ours (N#) and when I came out to her a few months ago, she was very supportive. Between us we hatched a plan for the next time I saw T#... and that time was today!
He was sharing a table at a zine fair with N#. When I walked up and said hi to N# he clearly had no idea who I was. I started talking to him. Still no sign of recognition. I said "When I saw you a few years ago at S#N# you said 'Look! I have beard!' and now I can say to you 'Look! I have boobs!'" Utter befuddlement, totally no clue, I don't think he even realised I was trans.
So N# and I started dropping some major clues about some of the art work I've produced that we knew he'd be very familiar with...
And suddenly his jaw dropped and eyes bulged as the penny dropped "When did THIS happen?!?!?!" - he was very happy for me, just utterly astonished.
hee hee!