Prince William and Princess Kate’s relationship has been well-documented, but there’s one romantic detail from their engagement that many don’t know about.

William and Kate pictured after their engagement in 2010

The Prince and Prince of Wales applaud

The much-anticipated moment came in 2010 during a trip to Kenya, where Kate left a touching keepsake in the guest book of their holiday lodge, seemingly commemorating the significant and romantic event.

The couple toured Kenya before settling at a lodge on Lake Rutundu. It was here that William found the perfect setting to ask the long-awaited question, reports the Mirror.

According to royal author Katie Nicholl, the pair spent the day unsuccessfully attempting to fish for rainbow trout before returning to their log cabin.

In the book, it was revealed that Prince William kneeled and proposed to Kate on a veranda.

Taking to heart the romantic ambience of her stay, the Duchess penned a charming message in the lodge’s guestbook before departing. “Thank you for such a wonderful 24 hours!” she wrote.

“Sadly no fish to be found but we had fun trying. I love the warm fires and candlelights-so romantic. Hope to be back soon, Catherine Middleton.”

In response, William added his own entry, writing: “20th-21st October 2010. Such fun to be back! Brought more clothes this time! Looked after so well. Thank you guys! Look forward to next time, soon I hope.”

News of their engagement remained hush-hush for some time, not going public until the following month. Interestingly, only a select few knew of William’s proposal plans during their Kenyan trip.

Even Kate’s own father, Michael Middleton, and Williams brother, Prince Harry, learned of the engagement late alongside everyone else. Recounting his surprise, Harry stated in his memoir Spare that he hadnt seen it coming.