Elizabeth Estensen (born 10 August 1949) is an English actress, known for portraying the role of Diane Sugden on the ITV soap opera Emmerdale from 1999 to 2021, with a guest stint in 2022. She has also made appearances in various British television series, including The Liver Birds, T-Bag and Coronation Street.

Estensen was born on 10 August 1949 and had a Norwegian grandfather, from whom she inherited her surname. She grew up in Stockton-on-Tees, County Durham. Her mother was a primary school teacher, and her father was a merchant seaman and solicitor's clerk. Estensen considered becoming a speech therapist, but signed up for a Drama and English teaching course at Manchester Polytechnic instead.^[2] Estensen has been married to husband Philip Allen since May 1983, and the pair have a son together, James Otto Allen.^[3]

Following graduation from Manchester Polytechnic, she moved to Liverpool and joined the Everyman repertory company. While appearing in a production of John, Paul, George, Ringo ... and Bert, she was noticed by actress Nerys Hughes, who was looking for a replacement for Polly James in her sitcom, The Liver Birds. Estensen was cast as Carol Boswell, her debut television role, in 1975.^[2] After The Liver Birds concluded in 1979, Estensen made appearances in films and series including T-Bag and Far from the Madding Crowd.^[2] Between 1996 and 1998, she appeared in the ITV soap opera Coronation Street as Pam Middleton.^[4] Then in 1999, she was cast in the ITV soap opera Emmerdale as series regular Diane Sugden, a role she has portrayed since.^[4] In 2007, she won a shared award at the British Soap Awards for Spectacular Scene of the Year, which saw a house collapse that her character was involved in.^[3] In September 2021, Estensen confirmed that she had filmed her final scenes as Diane in Emmerdale.^[5] Her final episode was broadcast on 29 October. However, Estensen agreed to return to the soap in October 2022 for a guest stint, for the show's 50th anniversary.^[6]