Bella Huntingdon was one of the last members of an otherwise extinct, tiger-like species. In her human form she looked like a pale, seventeen-year-old girl, though she could turn into a ferocious tiger.
Huntingdon came to Earth in the 18th century with her grandmother, Lady Huntingdon. Lady Huntingdon obtained an estate and held a ball every year, seemingly to find a husband for Bella. In fact, she was trying to get back to her home planet. When she wasn't needed, Bella was kept in a bare room and fed raw meat.
In 1764, Iris Wildthyme and Turner came to the ball. Iris planned to have Turner marry Bella and get the estate as an inheritance. Though Bella was interested, she knew Lady Huntingdon wanted Iris Wildthyme's TARDIS in return and denied Turner's proposal. When Lady Huntingdon was confronted by the Fourth Doctor, Bella refused to help her. After Lady Huntingdon's defeat, Bella remained on Earth and married Turner, who had been abandoned by Iris. (PROSE: Old Flames)