British actress Emily Kathleen Anne Mortimer was born in Hammersmith, London, England, to writer and barrister Sir John Mortimer and his second wife, Penelope (née Gollop). She was educated at St Paul's Girls' School in West London, and it was whilst there she began acting. Mortimer moved on from school to Lincoln College, Oxford University, where she studied English Literature and Russian, and spent two terms at the Moscow Arts Theater Drama School, studying acting.