The journalist and TV presenter said he is "very excited" to co-host with Susanna Reid three days a week from November.
Piers appeared on the show as a guest presenter earlier this year, and now he's bagged a permanent role within the presenting team.
"I am very excited at the prospect of waking up at 3am every morning, and even more excited by the thought of how annoying Susanna is going to find me after a few months," Piers said. "Good Morning Britain is a great show with a terrific team on and off screen. I'm looking forward to it enormously."
Managing director of daytime at ITV Studios, Emma Gormley, added: "We're proud of the strong show we've been building over the last 18 months and that audience figures are up some seven per cent year on year. We look forward to continuing that growth with Piers as part of the team."
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