Hortense

 was the teacher of Donna Noble's servants. Donna got her to teach Jacki Collins books. She was also Donna's maid and helped to make Donna's wedding dress.

When the Tenth Doctor believed that Donna would marry Rudolph, he asked Hortense if she would like to travel with him. She declined on the fact that she was busy with her job. (AUDIO: Death and the Queen)