The presenter was left red-faced when he asked her a tough maths question in order to prove his belief contestants on the ITV2 reality series are “thick” - only to get the answer wrong himself.
Piers, who has been a long-time critic of ‘Love Island’ and its participants, asked Hayley if she knew “Pythagoras’ theorem to the nearest five decimal places”.
After she didn’t even hesitate in telling him she couldn’t, Piers’ co-host Susanna Reid turned the tables on him, and asked: “Well, do you?”
He answered with 3.147 (which isn’t even to five decimal places as his original question asked), but the crew took great delight in telling him his question was completely wrong in the first place.
Rather than Pythagoras’ theorem, which relates to the measurements of a triangle, he meant to ask about the mathematical constant Pi, which is the ratio of a circle’s circumference to its diameter.
And even then, Piers’ answer was wrong - Pi to five decimal places is 3.14159.
“You just showed yourself up, Piers Morgan, on national television, in an attempt to humiliate these people,” Susanna told him.
“You know what’s just happened to me? I’ve just been mugged off,” he joked, referring to one of the show’s famous catchphrases.
Despite his heavy criticism of ‘Love Island’, Piers had claimed never to have actually sat down and watched an episode - until last week, that is, when he revealed on Twitter that he’d finally tuned in.
“Accidentally stumbled across Love Island,” he claimed. “My God, these cretins are even more stupid than I feared.”
However, he ended up being rinsed, while former contestant Camilla Thurlow schooled him on why his “thick” jibes are wrong.
Meanwhile, Hayley has also spoken out to defend herself after she made headlines while in the villa for not knowing what Brexit was.
After famously asking her fellow Islanders if leaving the EU would mean the UK had fewer trees, she stood by the comments in an interview with Lorraine Kelly on Monday.
“I don’t really understand, if you want me to be honest. I really don’t think many 21-year-olds know about Brexit,” she said.
“But, obviously, because I’ve been the one to open my mouth and not just sit back, it’s me that has been judged.”
‘Love Island’ continues on Wednesday at 9pm on ITV2. ‘Good Morning Britain’ airs weekdays from 6am on ITV.