The actress will return to filming at the BBC One soap in January after three years away from the programme.
Stacey was last seen fleeing the country after Janine Butcher (Charlie Brooks) exposed her as the killer of Archie Mitchell.
While exact details of her comeback storyline have yet to be revealed, show bosses are promising that Stacey's shock return will be one to remember.
Turner commented: "I may have left EastEnders over three years ago, but the show has always been in my heart, as has Stacey, and she has never really left my side.
"I am so excited about returning and seeing what the future holds for her. It's been a while since I set foot in Albert Square and I am looking forward to coming home."
EastEnders' executive producer Dominic Treadwell-Collins added: "Stacey is one of EastEnders' best-loved characters, played by one of television's finest actors and I am tremendously excited that Lacey has decided to return home to Walford.
"Stacey's last time on the Square was iconic. But that was just the first act. There is so much more to come for Stacey - and her return will send ripples of drama through the Square."
Turner's original stint as Stacey ran between 2004 and 2010, during which time she won over 30 awards for her portrayal of the character.
Stacey was also at the centre of huge storylines, including her affair with father-in-law Max (Jake Wood) and the shock reveal in EastEnders' 25th anniversary live episode that she was responsible for Archie's murder.
Since leaving EastEnders, Turner has appeared in a number of other shows including Being Human, True Love, Bedlam, Switch and Our Girl.
As well as returning to EastEnders, Turner will be filming a five-part series of Our Girl next year.
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