Her most famous characters on her self-titled sketch show were Bernie the Irish nurse, the jumpy Margaret, and spoiled Aga Saga.
In 2011, she was cast as Nellie Bertram on The Office and became a series regular soon after.
She based her character of Margaret, who would be spooked by the smallest of sounds, on her mother, Josephine. She and her then boyfriend, Twig Clark, welcomed a daughter in 2003.
She starred opposite David Tennant, the tenth Doctor, on Dr. Who.