Ms Kelly, 54, is leaving the breakfast programme later this year but will now host her Lorraine show five days a week instead of the current four.
She said: "I'm delighted to have signed up for another three years at ITV. I thought long and hard about staying on at both shows but have decided I really want to focus on my show."
BBC Breakfast presenter Mrs Reid has agreed to switch channels in a £1 million deal, according to reports.
The 43-year-old's profile soared after reaching the final of the popular Strictly Come Dancing and it is believed she was keen to boost her profile.