Show bosses are keeping the exact details of her storylines under wraps, but it's been confirmed that the former Girls Aloud star will appear in four episodes.
We've also been told Sarah will play a feisty character, who is going to make life difficult for troublemaker Tracy Barlow!
Sarah said: "I am extremely excited to be joining Coronation Street. As a fan of the show it is a huge honour for me to join the cast. I can't wait to get started!!"
Sarah, whose acting credits include Bad Day, the BBC television film Freefall, Run for your Wife and St Trinians 2: The legend of Fritton's Gold, will start filming in May.
She added on Twitter: "Yes it true I'm joining Corrie!!! As u all know I've been a huge fan for yrs now so can't wait to strut my stuff on those famous cobbles!"
Producer Stuart Blackburn said: "Sarah is proving to be a gifted and exciting actor and I'm absolutely delighted to have her on board, the viewers are in for a treat as her character will be right at the heart of a massive new story for the Barlows."
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