The Duke of Sussex recalls the escapade in his forthcoming memoir Spare, which is due for release on Tuesday (10 January) but leaked after it was accidentally released five days early in Spain.
You can read more about the biggest revelations from the book on The Independent’s live blog.
One of the most shocking stories in the book is the story of the first time Harry had sex, with the royal claiming he lost his virginity to an older woman in a field behind a “very busy pub”.
Harry refers to the incident as “a humiliating episode with an older woman who liked macho horses and who treated me like a young stallion”, adding: “I mounted her quickly, after which she spanked my ass and sent me away.”
The subject was raised during Friday’s episode (6 January) of This Morning, with hosts Hammond and Dermot O’Leary joined by Gyles Brandreth and Vorderman to discuss the book.
After talking about an alleged altercation between Prince William and his brother, Hammond asked about the story.
“This is where the juice of the interview comes from,” O’Leary joked, before comparing it to a scene from Lady Chatterley’s Lover or Atonement.
“Aged 16 or 17, in a field near school, an older woman took his virginity,” Brandreth said. “And then, when the act of darkness completed, he lay on his front and she smacked his bottom and sent him on his way.”
Hammond erupted in a high-pitched laugh, while Brandreth looked down the camera and joked: “Other channels are available.”
This made Hammond laugh even harder, while Vorderman lay down on the sofa.
“I’m sorry, it’s in the book,” Brandreth joked.
Vorderman then tried to retell the story, but couldn’t get her words out due to laughter.