The episode will be set in 1979.
EastEnders has announced a special flashback episode which will see the return of a much-beloved character.
The soap is currently filming scenes for the episode which will air this autumn and centre around the Mitchell family.
Jaime Winstone will be playing Mitchell matriarch Peggy Mitchell, the character that was made famous by the late Dame Barbara Windsor. Winstone previously played Windsor herself in BBC biopic Babs.
Alongside Peggy, the episode will also feature characters from EastEnders history that have never appeared on screen before, such as Peggy’s husband, Eric (George Russo), Billy Mitchell’s older brother, Charlie (Charlie Heptinstall) and Billy and Charlie’s father, Stephen (Dean Roberts).
The cast will also include Daniel Delaney as Phil, Teddy Jay as Grant, Henry Garrett as Archie, Rose Reynolds as Glenda and George Greenland as Billy.
The episode will be set in the winter of 1979 as the Mitchells are hit hard by a Britain in economic turmoil and Peggy struggles to take care of Phil, Grant and Sam, while her marriage to Eric hits the rocks.
Meanwhile, tensions are rising between Phil and Eric as they compete for the title of man of the house, and Glenda is doing her best to keep Ronnie and Roxy out of trouble.
The episode will mark the beginning of a tumultuous journey for Phil as he is forced to confront his past and how it affects his present and future.
Speaking about her casting as Peggy, Jaime Winstone said: “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.
“There’s certainly a healthy amount of pressure when you’re taking on such an iconic role – I thoroughly enjoyed it.
“Playing this role has really cemented my love and admiration for Barbara as I got to bookend my journey by playing Peggy Mitchell – I hope I’ve done her justice. I’ve loved every minute of it and I can’t wait for everyone to see the episode.”
Chris Clenshaw, Executive Producer, added: “We’re delighted to be welcoming an incredible cast of actors to set for this special flashback episode, including the luminous Jaime Winstone as a young Peggy Mitchell.
“Focused on the Mitchell family, audiences will embark on a rollercoaster journey to the East End of London in 1979 where they’ll delve into the family’s past, seeing much-loved and iconic characters, as well as meeting characters from the show’s history that have never been seen on screen before.
“There are twists, turns and secrets revealed – after all, trouble is never too far away where The Mitchells are concerned!”
EastEnders airs on Mondays, Tuesdays, Wednesdays and Thursdays at 7.30pm on BBC One, with some episodes airing on BBC Two during summer sporting events. The show also streams on BBC iPlayer.