Kathleen "Kat" Moon (also Slater) is a fictional character from the BBC soap opera EastEnders, played by Jessie Wallace. She was also played by Kate Peck in a flashback in 2001. Kat is the daughter of Viv Slater and Charlie Slater (Derek Martin), and arrived with her sisters Lynne Hobbs (Elaine Lordan) and Little Mo (Kacey Ainsworth). Her daughter Zoe Slater (Michelle Ryan) is initially believed to be her sister as well until Kat reveals she was raped by her uncle Harry Slater (Michael Elphick) as a child. She later marries Alfie Moon (Shane Richie). It is later revealed that Kat also gave birth to a son, Zoe's twin brother. She appeared in the show from September 2000 to November 2004, then returned in May 2005 following a period of maternity leave. She left on 25 December 2005, and retur