Discussing the role, Friedman said: "I am thrilled to be joining the cast of EastEnders to play Elaine Peacock. Working alongside Kellie Bright and the rest of the Carter clan has been an absolute joy. It has also been a lovely experience to take my West End shoes East for a short trip!"
Executive producer Dominic Treadwell-Collins added: "Ever since Elaine became the voice on the end of the Queen Vic phone, we have been waiting to see just what kind of woman made Linda Carter. Elaine is tough, warm and capable - but also proud and more than a little vain, bringing with her a whole new dynamic when she arrives in Walford to sort out her daughter.
"Maria Friedman is a West End legend and we are all very excited to have someone of her pedigree playing Elaine Peacock."
Friedman is the latest West End star to be cast in EastEnders, following in the footsteps of Declan Bennett (Once) and Danny-Boy Hatchard (Beautiful Thing). She was most recently nominated for an Olivier Award for her direction of Merrily We Roll Along. She has won the Olivier Award for Best Actress in a Musical twice for her performances in Passion and Ragtime.