It's a Time Lord costume from the classic Doctor Who Series. I'm not sure if David was wearing it while he was the Tenth Doctor and he was goofing off on break or something like that.
Actually, Yes it is. If you have seen the DVDs of two 4th Doctor stories, "Invasion of Time" and "The Deadly Assassin" or the story from the 5th Doctor era, "Arc of Infinity" They did wear a cosrtume like what David is wearing in the picture. You must be thinking of what the Master was wearing in the 1996 Doctor Who Movie. It was a more styilized version of the same costumne.
I'm not sure, so don't take my word for it, but that looks like the sort of thing the older TimeLords used to wear.... so possibly something to do with DW
