Susanna Reid insists Prince Harry has the right to "tell his own truth" after it emerged he is to publish a literary memoir next year.
The Duke of Sussex said it would be an "accurate and wholly truthful" account of his life.
It will cover his lifetime in the public eye, including his time in the military, marriage and fatherhood, the Mirror reports.
Read more: Prince Harry to publish 'wholly truthful' book on his life next year
Harry said the memoir, to be published by Penguin Random House, will be written "not as the prince" he was, but as the man he has "become".
He said: "I'm writing this not as the prince I was born but as the man I have become.
"I've worn many hats over the years, both literally and figuratively, and my hope is that in telling my story - the highs and lows, the mistakes, the lessons learned - I can help show that no matter where we come from, we have more in common than we think.
"I'm deeply grateful for the opportunity to share what I've learned over the course of my life so far and excited for people to read a first hand account of my life that's accurate and wholly truthful."
Discussing the announcement on Good Morning Britain with co-host Ben Shephard, Susanna supported Prince Harry over the plans.
"Look, I don’t think it’s unreasonable for Prince Harry to define the kind of privacy that he wants," Susanna said.
"He’s talked about how he found it really traumatic just constantly being covered by paps and the experience that his mother had.
"I think it’s a little disingenuous when people say, ‘oh you wanted privacy and you went away and now you’re doing a book’," she continued.
"In their words, he wants to tell his own truth, he wants to be in charge of his own story."
Ben seemed to agree with Susanna and added: "There is a huge part of his story that people will be keen to know about, as a child growing up, going to school, being in the army, the hugely important role he played in the army that we're all very proud of him for doing.
"Where he certainly, like much of our armed forces, could be considered a hero.
"There's a huge swath of the country that would love to understand more about what he went through and what that taught him about who he is now," Ben added.
Good Morning Britain airs weekdays at 6am on ITV.
