Susanna has been announced as one of four new presenters of the programme, which will replace Daybreak and will launch later this year.
Joining Susanna on the sofa from 6am to 8.30am will be Ben Shephard, Sky News presenter Charlotte Hawkins and journalist Sean Fletcher.
Meanwhile Lorraine Kelly will continue to host Lorraine at 8.30am and current Daybreak host Aled Jones will be fronting a new weekend show called Weekend.
Helen Warner, ITV's director of daytime, said: "I'm delighted to welcome all four presenters to the ITV Breakfast family. ITV has a first class roster of breakfast and daytime talent both on and off screen and I'm thrilled to be expanding this.
"Our overriding aim is to continue to improve our breakfast programming for our viewers and we have been working for some time behind the scenes developing the next chapter of our offering."
She added: "Engaging, news driven content is our number one priority and will be at the heart of everything we do on Good Morning Britain.
"I believe we have a top team in place to deliver this and make this a compelling proposition to wake up to in the morning."
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