Tallulah was an actress and singer in New York City in 1930. She was the lead singer of New York Revue, a stage act where the other showgirls dressed as devils, while she was dressed as the lone angel.
Tallulah worked in a theatre called the Laurenzi, where she fell in love with one of the stagehands, Laszlo. She was a bit of a ditzy person and easily confused when walking in underground tunnels, but her will was hard as iron. When Laszlo was taken by the Cult of Skaro's minions, Tallulah missed him. He was partially converted into a pig slave, but still left her a rose every day.
Tallulah followed the Tenth Doctor into the sewers in order to find Laszlo. (TV: Daleks in Manhattan) She helped the Doctor, along with Martha Jones and Laszlo, to stop the Daleks. After the Daleks' defeat she stayed with Laszlo, despite his altered appearance, showing that she truly loved him. (TV: Evolution of the Daleks)