A soothsayer was a member of the Sibylline Sisterhood in Pompeii in 79 AD. She had eyes painted on the back of her hands — a sign of the cult. She was the first of the Sisterhood to see the TARDIS, or "Blue Box", that had appeared in a prophecy. She had psychic powers from breathing in dust from Vesuvius that was converting her into a Pyrovile, and could see through time because of the rift activity there. (TV: The Fires of Pompeii)
Karen Gillan was later cast as Amy Pond, first companion of the Eleventh Doctor, beginning in series 5. Coincidentally, Amy had an affinity for Romans. Unlike other guest actors who later played more prominent characters (such as Lalla Ward or Freema Agyeman), no attempt was made, either on-screen or in behind-the-scenes interviews, to connect the soothsayer to Amy.