Actress Jessie Wallace, who plays Kat Moon in EastEnders, is to leave the series at the end of the year, the BBC has confirmed.
Wallace has been in EastEnders for almost five years
The 33-year-old will exit the soap in an undisclosed storyline, said a spokesman for the programme, adding the decision was "mutual".
Wallace is in talks with the BBC to work on other projects after her departure from the show, he continued.
The actress has played the role in the BBC soap since 2000.
"As a newcomer we found an amazing talent in Jessie and we thank her for a fantastic contribution to the show," said the EastEnders spokesperson.
"Jessie and the writers want Kat Moon to go out on a high."
Charlotte Avery, who plays Tina Stewart, will also be leaving the Square later this year.
Wallace joined the soap along with the rest of the Slater family almost five years ago, and was at the centre of a series of hard-hitting storylines.
Her character admitted to sister Zoe Slater that she was actually her mother, and that her Uncle Harry was her father.
Kat Slater was poised to marry gangster Andy Hunter, but was rescued at the last minute by Alfie Moon, played by Shane Richie.
The pair married and took charge of the soap's infamous Queen Victoria pub, but their happiness was soon destroyed as Hunter wreaked his revenge.
In 2004 Wallace took maternity leave from the series, during which time EastEnders was criticised in the press for having declining viewing figures and weaker storylines.
Her character returned to the soap earlier this year to witness the departure of screen daughter Zoe, played by Michelle Ryan, and the further decline of her romance with Alfie.
EastEnders is hoping to rejuvenate its fortunes with the return of Peggy Mitchell and her sons Grant and Phil.