The journalist-turned-presenter launched into a fresh tirade at the beginning of the episode, accusing the Duke of Sussex of “whining” about the circumstances surrounding the latest royal crisis.
As Morgan mocked Harry and labelled him “pathetic”, Reid grew visibly fed up of her co-host and gave him a taste of his own medicine by talking over him.
She said: “So he's decided to give up all the palaces and the servants and the royal funding and he wants to have a more peaceful life.
“And I don't know why you have to keep having a go at him.”
Morgan then mockingly cooed: “Ooo, poor Harry”, to which Reid replied: "Why do you have to act like that? It's not pathetic, he's made a decision.
“Let them do what the hell they like and stop having a go at them.”
When Morgan claimed Harry and Meghan “never stop yapping”, Reid already had a response ready.
“You never stop yapping!” she said, raising her voice. “It's so ironic, you're so hypocritical.
“‘Me, me, me, it's all about me,’ and you have a go at Prince Harry. You have a go at him all the time.”
Since the latest royal crisis kicked off earlier this month, Morgan has launched numerous tirades - both online and on GMB - about Harry and Meghan’s decisions.
The couple announced earlier this month that they would be stepping back from royal duties and working towards becoming more financially independent.
On Sunday (January 20), Harry admitted he was doing so “with great sadness”, stating that he had “no other option.”
“The decision that I have made for my wife and I to step back, is not one I made lightly,” he said during a speech at a charity event.
“It was so many months of talks after so many years of challenges.”
Good Morning Britain airs weekdays from 6am.