The actress - also known for her parts in Tenko and Waiting for God - will begin filming with the soap in the New Year and make her first appearance on screen in March, when Sylvie turns up in Weatherfield to stay with Roy and Hayley.
According to Corrie's official website, Sylvie has an outspoken attitude and soon makes her mark on the street following her arrival.
Speaking of her casting, Cole commented: "I am absolutely delighted to be joining. In any great drama - be it on television or on the stage - the writing comes first, and Coronation Street is brilliantly written.
"When I worked at Granada Television a lot in the 1980s, I used to play bridge with Doris Speed and I remember thinking, 'Maybe one day they will offer me a role on Coronation Street'. Well that day has finally come and I am thrilled.
"I am a huge Roy and Hayley fan, so to be joining their family on screen is a privilege for me and I can't wait to get started."
Corrie's producer Phil Collinson added: "I am delighted to welcome Stephanie Cole to the cast. I have long been an admirer, from the brilliant dramatic performances she gave in Tenko, to the side-splitting Diana in Waiting for God - she is one of this country's finest actors. Life at Roy's Rolls is never going to be the same again."
News that one of Roy's family members would join Coronation Street first emerged in October, when the new arrival was tipped to "put the cat among the pigeons" for Roy and Hayley. Get the Inside Soap magazine on your iPhone or iPad