She was born in Lewisham in 1972 and brought up in Brighton. As a teenager she was part of the National Youth Theatre company, and in 1993 played the First Midwife in Peter Greenaway's The Baby of Mâcon.
She teamed up with future Spaced co-star Katy Carmichael in a stage double-act called The Liz Hurleys, then went on to television parts in the nursing drama Staying Alive (1995-7) and short-lived sketch shows Six Pairs of Pants and Asylum where the Spaced team of Stevenson, Simon Pegg and Edgar Wright first assembled.
In 1998 she was cast in the supporting role of neighbour Cheryl in sitcom The Royle Family, which became a surprise hit, and in 1999 cowrote and starred in Spaced. Since then she has had parts in Bob and Rose on TV, Born Romantic on the big screen and also on the West-End stage and has been signed up to write and star in a Hollywood spy comedy called Double Au Pair.