The tuxedo the Doctor wears has made two previous appearances, first in "The Age of Steel"/"Rise of the Cybermen" and then again in "The Lazarus Experiment". The Doctor tells Martha Jones that bad things always seem to happen when he wears it.
“i’m the doctor. i’m a time lord. i’m from the planet gallifrey in the constellation of kasterborous. i’m 903 years old and i’m the man who is gonna save your lives and all 6 billion people on the planet below. you got a problem with that?”