The 80s singer will make her first appearance when the show returns this September.
The soul star, famous for hits including My One Temptation and Where Is the Love, will play Ellie Nixon, who reportedly has a "shock connection" to an existing character.
Mica said: “I am absolutely over the moon to be in EastEnders.I have been a fan since its first episode with Susan Tully being my favourite. My character the formidable Ellie Nixon, is a new frontier for me as an actress - a lot of folks will see me as never before.”
EastEnders returns Monday 7th September on BBC One.