And by Peggy Mitchell we mean Barbara Windsor, who will reprise her role, as the iconic former Queen Vic landlady for one episode next year.
Speaking on her return to the BBC One soap, the 77-year-old said: ''I am absolutely thrilled that Peggy has been included in the celebrations to mark the 30th anniversary of EastEnders.
“What an incredible achievement for all the production, cast and crew, past and present."
The Carry On actress surprised fans when she made an appearance in September, again for one episode, to express the displeasure with her ‘son’ Phil Mitchell’s impending marriage to Sharon Watts.
EastEnders executive producer Dominic Treadwell-Collins told Digital Spy: "Barbara and Peggy are intrinsically linked with EastEnders and when we planned our explosive anniversary episodes, Peggy was the first name on our list of hoped-for returns.
"Barbara has not only created one of EastEnders' most iconic characters but she's also hugely loved and missed by everyone here. We couldn't celebrate 30 years of EastEnders without Barbara Windsor."
The show, which first aired on February 19 1985, will celebrate its 30th year with a 30-minute live episode, as well as several live scenes in the other episodes of that week.
Barabara took on the role of Peggy in 1994, and went on to become one of the show's most popular stars before leaving the soap in 2010.