The special episode will air on 14 November for Children In Need, and will see Gillian Taylforth (Kathy), who was Ian's mum, Pam St Clement (Pat), and Michelle Collins (Cindy), Ian's ex-wife, all appear in Ian's subconscious, as well as the ghost of his dead daughter, Lucy Beale, played by Hetti Bywater.
Adam Woodyatt who plays Ian said: "I never thought I would see the day where I was reunited with Gillian, Pam, Michelle and Hetti, so to work with them all again and for such a great cause was an absolute dream.
"It was one of the best days I have ever had at work. As soon as we got on set it was like none of them had ever left."
He continued: I don't want to spoil it but Ian is really happy to see some faces and completely knocked for six by others, but then again I think finding your late ex-wife in your kitchen is enough to shock anyone."
Producers added that Ian would be confronted by the women from his past including his "adulterous, home-wrecking ex-wife" Cindy, and mum Kathy, who has a surprising new love interest, in various iconic locations around Albert Square.
Gillian played Kathy on the BBC soap between 1985 and 2000 and said it was "surreal but fantastic" to be back on the set.