You mean like how Madame Vastra, Jenny Flint, and Strax were introduced to the audience? None of them were established previously to the viewers but they knew the Doctor; Vastra apparently knowing him quite well too.
Slight nitpick, but A Good Man Goes to War is the first time Jenny met the Doctor. She didn't even recognize the TARDIS in that episode.
And yet, "The Name of the Doctor" implies that they had met before that.
Right before Jenny disappears, Vastra says, "He saved your life when we met." Although I suppose Jenny could have been unconscious or something...
