Bill Potts' mother

Bill Pott's mother is, as her name suggests, the mother of Bill Potts, the companion of the Twelfth Doctor.

History
At some point in her life, she got pregnant and gave birth to a daughter, Bill. She died some time afterwards, when Bill was still young enough no to have any memories of her. Bill states that she hated having her photo taken. However, at various points in her life, the Twelfth Doctor would appear to take photo's of her in order to give these photo's to Bill as a daughter.

Appearance
Bill states that she looks liker mother- and the photos the doctor took reveal that mother and daughter are indeed very similar in appearance.