Danniella Westbrook has said she is "really excited" to be returning to EastEnders after a six-year absence.
The actress and reality television star, who has fought a high-profile battle with drug addiction, will step into Albert Square for several episodes of the BBC soap later this year.
She will make a "brief appearance" as Samantha Mitchell in special episodes showing the funeral of her on-screen mother Peggy (Barbara Windsor) after her death from cancer, a spokesman for the soap said.
Westbrook, 42, said: "I'm really excited to be going back to EastEnders. It feels right that the Mitchells are all back for Peggy's funeral and I can't wait to work alongside everyone again."
Westbrook has played Samantha, the sister of Phil and Grant Mitchell, in the soap on and off since 1990.
The actress has fought cocaine addiction, which at a low point left her with a completely eroded nasal septum. She has written books on her experiences and spoken about her struggle in interviews.
She also appeared on the latest series of Celebrity Big Brother, finishing fifth in February's finale.
EastEnders executive producer Dominic Treadwell-Collins said: "It is only right that all of Peggy Mitchell's children would be at her funeral. Danniella is the final piece of the Mitchell jigsaw puzzle so it will be great for viewers to see Phil, Grant and Sam all back on screen.
"Danniella will only be back for a few episodes but these scenes are bound to go down in EastEnders history."