Lawrence came to public attention as a regular guest on the Channel 4 improvisational comedy series "Whose Line Is It Anyway?" at its launch in 1988. Lawrence's speciality on "Whose Line" was her ability to improvise songs on the spot. She was the first female performer to perform regularly and featured on the show until 1997, which was the final UK series to be made in London. She also performed in two episodes of the American edition of the show in 1999.