She is an icon of British soap and her character is adored by the millions of fans of the show.
As she prepares for a steamy new storyline, Digital Spy brings you a few quick-fire facts about the Albert Square favourite.
1. Jessie Wallace was born Karen Jane Wallace on September 25, 1971 in Enfield, North London. Her father James was a telecommunications engineer and her mother was a secretary. At the age of 3, Jessie's parents divorced and she and her sister lived with their father. Their mother stayed part of their lives as they saw her at weekends.
2. Wallace left school at the age of 15 and tried her hand at several different jobs. At 21, she moved to Portugal for seven months to work in holiday bars. On returning to Britain, she decided that she wanted to be a make-up artist and went on a two-year course at the College of East London. After her studies, Jessie got a job at the Royal Shakespeare Company for two years.
3. Jessie decided that she would rather be an actress than a make-up artist and began auditioning for acting courses in secret. She was recalled for further auditioning at RADA but did not make it on to the programme. She then got on to a two-year course at the Poor School. The course was in the evening which meant that Jessie had to quit her job, prompting her to begin wig-making during the day to fund her studies.
4. Her first television appearance was in an episode of ITV's The Bill in 1999. She also originally auditioned for another part in EastEnders after graduating from the Poor School but she didn't get it. However, the producers of the show instantly thought of her for their new Slater family and offered her the part of Kat.
5. Although she is strongly affiliated with EastEnders, Jessie crossed over to the cobbles of Corrie in December 2010 to play British soap sex siren Pat Phoenix in The Road to Coronation Street, a one-off drama that showed the creation of the much-loved soap for its 50th Anniversary. She was nominated for a 'Best Supporting Actress' BAFTA for her portrayal.
6. She has made many guest appearances on television. These include The Dinner Party with Alison Steadman and Lee Evans and A Class Apart, as well as a hosting stint on a special edition of The Friday Night Project. She also took Kat Slater out of Walford for the 2005 French and Saunders Christmas Special.
7. Jessie was once suspended from work by the BBC for drinking to excess and adverse publicity. After her return to the soap, she found herself in yet more trouble when she was arrested for driving one and a half times over the limit. While attending court for the the crime, she met policeman Dave Morgan and the couple now have daughter Tallulah Lilac.
8. Jessie is quite a keen singer. In 2007, she replaced Denise Van Outen in the West End production of Rent Remixed at the Duke of York's Theatre. She played the title role in Miss Marie Lloyd - Queen of The Music Hall on BBC Four in 2007. She got the part after singing a version of 'The Boy I Love Is Up in the Gallery', one of Lloyd's songs.
9. Jessie is only 26 years younger than Laila Morse, who plays her grandmother Mo Harris in EastEnders. Also, despite playing her older sister in the soap, Jessie is three years younger than former co-star Kacey Ainsworth.
10. Jessie in numbers: She was one of 16 EastEnders actors to have competed in BBC's Strictly Come Dancing; she has won 21 awards for her portrayal of Kat Slater; the character appeared twice in the 2010 50 Greatest EastEnders Weddings of All Time - in position 14 for her wedding to Andy Hunter and 4 for her wedding to Alfie Moon.