Kitty Donaldson was Molly O'Sullivan's employer. She volunteered, as did the rest of her household, as part of the Voluntary Aid Detachment and helped on the front line in France during the First World War. She fell ill after being infected by a gangrenous leg, and Molly cared for her. When time winds bled into France during the First World War, she was killed by corrosive time. (AUDIO: The Great War)
Due to Kotris's plan to destroy the Time Lords being erased from time, she didn't die. (AUDIO: X and the Daleks)
She had a brother named Martin Donaldson. She told the Eighth Doctor to look at Martin. She later followed the Doctor to the Ritz and around town to find her brother and Liv Chenka. (AUDIO: A Life in the Day)