Peggy Mitchell is set to return to EastEnders in a flashback episode looking into her and her family's past.
A younger version of the famous fictional landlady will be played by Jaime Winstone, the BBC confirmed.
Mitchell, the matriarchal leader of the family, was most notably portrayed by the late Dame Barbara Windsor.
Dame Barbara joined the soap in 1994, becoming one of its biggest stars. She died in 2020 aged 83 after living with Alzheimer's disease for six years.
Before the actress joined the soap full-time, Peggy Mitchell first appeared as a guest character in 1991, played by Jo Warne.
Winstone, the 37-year-old daughter of actor Ray Winstone, has previously portrayed a younger version of Dame Barbara herself in the BBC biopic Babs in 2017.
"It's been such an honour to step into Peggy Mitchell's shoes for the first time, and into Barbara's shoes for the second time," she said.
"There's certainly a healthy amount of pressure when you're taking on such an iconic role - I thoroughly enjoyed it."
Playing the role, Winstone said, had "really cemented my love and admiration for Barbara," adding she hoped she had "done her justice."
The forthcoming episode, which will broadcast in the autumn, will also feature a mix of current characters alongside ones who have never been seen on screen before.
The line-up includes Peggy's husband Eric (George Russo), Billy Mitchell's older brother Charlie (Charlie Heptinstall) and Billy and Charlie's father Stephen (Dean Roberts).
It will take viewers back to the winter of 1979 with the Mitchell family "hit hard by a Britain in economic turmoil" and Peggy struggling to keep things afloat as her marriage to Eric is "showing its cracks".
Audiences will also be taken on a journey back to present-day Phil's (Steve McFadden) youth where "clues to his present will undoubtedly be revealed", a spokesman for the soap said.
Chris Clenshaw, EastEnders' executive producer, said the episode will "delve into the family's past".
"There are twists, turns and secrets revealed - after all, trouble is never too far away where the Mitchells are concerned," he added.
Last week it was announced that Bobby Brazier, a model and son of late reality-TV star Jade Goody, was set to join the soap as Freddie Slater, the son of Little Mo.