Prince William shocked the world with his foul-mouthed language during an interview on Monday night (04.01.16).
The 33-year-old royal was chatting as part of 'When Ant and Dec Met the Prince: 40 Years of the Prince's Trust'.
But a storm was caused on the Internet when he swore during one segment of the programme.
While he described letters he used to receive from his father, Prince Charles, during his time at Eton, William explained that he and his brother Prince Harry often struggled to make sense of the handwritten notes but worried they might contain a "b*****king" from their dad.
Prince Charles is known for his bad handwriting, meaning his letters to Government Ministers are nicknamed "black spider memos".
William and Harry also revealed their father has always shunned the idea of modern technology, much preferring the old-fashioned letter as a means of communication.
Recalling how Charles often stays up late writing letters, William explained: "As it gets later in the evening, when it's about 12 o'clock he's writing letters, we can tell instantly because it starts going off the page when he's falling asleep."
Harry added: "At school we regularly swapped letters and said "I think I know what it says can you read it to me?"'
William then laughed: "Just in case it was a b*****king we didn't know about!"