The 22-year-old actress is quitting the soap to pursue a career in film.
Lacey said: ‘I’ve had the most fantastic time at EastEnders,’
‘Stacey’s been a brilliant role – as has being part of the feisty Slater family.
‘I’m so lucky to have had such challenging storylines, from the affair with Max and being diagnosed as bipolar, to the shock of being revealed as Archie’s killer in the live episode.
‘I’ll miss everyone in Albert Square, but the time has come to try something different.’
Lacey’s final scenes will air later this year.