BoondocksMoon said:
Who is Princess D
The princess from Act 4, whose ball was infiltrated by Moon/Mercury/Mars, as well as Tuxedo Kamen and Nephrite, all looking for the Silver Crystal. Her name in the anime was "Princess Dia", where she appeared in episode 22 (the episode where Usagi and Tuxedo Kamen fall off a balcony together and float down via an umbrella).