Regina Bartholomew

From Memory Alpha, the free Star Trek reference.

Countess Regina Bartholomew was a holographic figure created aboard the USS Enterprise-D as a part of Data's holoprogram based on Sherlock Holmes. She was the consort of James Moriarty.

In 2369 Moriarty, who had become self-aware, briefly commandeered the Enterprise in order to win his release from the holodeck. After Captain Jean-Luc Picard convinced Moriarty that he was released from the holodeck, Moriarty asked that Regina also be released so he could spend his life with her. He was given a shuttlecraft, and Regina set off with him on a voyage through the galaxy. Unknown to them, it was a holographic trip, a ruse devised to convince Moriarty to return control of the ship to Picard. At the start of their journey the Countess expressed a strong interest in visiting Earth. (TNG: "Ship in a Bottle")

Regina Bartholomew was played by Stephanie Beacham.