A slight slip of the tongue

Had yet another one of my obtuse moments at work today. There is this high maintenance client that the case managers have nick named J-Lo. I know the client's real name, but when I got the phone call from the client I put the client on hold and shouted over the wall to the case manager "Jennifer Lopez (not the client's name) is on the phone". I did not do this in jest, even though I know the client's real name, my mind was set on calling her Jennifer Lopez. I had not realized my faux pas until a couple hours later the giggling co-workers came to me and told me what I said. They had to explain it to me twice before I understood, then my giggles joined theirs.