The 51-year-old north London-born star began filming scenes in summer and will debut as Ellie Nixon in September.
Paris released her debut album So Good in 1988, which peaked at number six in the albums chart, before diversifying into presenting, co-hosting the BBC consumer fashion programme What Not To Wear.
She has also appeared on stage in Love Me Tender, Chicago and the West End production of Fame.
According to the BBC, Nixon is “a wolf in sheep’s clothing, with far more to her than her warm-hearted facade lets on”.
Her arrival in Albert Square will reveal a surprising connection to Walford’s current residents.
Paris said: “I am absolutely over the moon to be in EastEnders. I have been a fan since its first episode, with Susan Tully (Michelle Fowler) 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 executive producer Jon Sen said: “We’re thrilled to welcome Mica Paris to the world of Walford to play tough, no-nonsense Ellie Nixon.
“Ellie proves herself to be a ruthless and uncompromising force of nature who stops at nothing to ensure she capitalises on whatever she can.
“The part demanded both charisma and presence and, having seen Mica on stage, she was the first person who came to mind for this role.
“We can’t wait for the audience to meet Ellie and the mystery that surrounds her.”
It comes after show bosses confirmed that EastEnders will return on September 7 after nearly three months off air.
Filming – which was paused because of coronavirus restrictions – resumed at the end of June.
Additional reporting by Press Association.