The Prince of Wales celebrated St David's Day on Saturday, and, paying homage to his role, the royal delivered the message in Welsh.
In a video shared by Kensington Palace, William said: "Helo. Heddiw, ar Ddydd Gŵyl Dewi, rydym yn dod at ein gilydd i ddathlu Cymru – ei hanes, ei diwylliant, a'i phobl anhygoel. O'i golygfeydd anhygoel i'w hiaith, mae Cymru yn parhau i ysbrydoli. Heddiw, rydym yn dathlu popeth sy'n hudol am Gymru. I holl bobl Cymru ac i bawb ledled y byd, Dydd Gŵyl Dewi hapus."
The message translates into English as: "Hello. Today, on St. David's Day, we come together to celebrate Wales — its history, its culture, and its incredible people. From its breathtaking landscapes to its language, Wales continues to inspire.
"Today, we will celebrate everything that is magical about Wales. To the people of Wales and everybody around the world, Happy St David's Day."
Although William will regularly speak to Welsh people in their native tongue, this marks the first time that the royal has delivered a full message in the language.
HELLO! understands that while William is not taking full-time Welsh lessons, the father of three has been learning conversational Welsh.
The video was shared alongside the words: "Happy St David’s Day from The Prince of Wales. Dydd Gŵyl Dewi Hapus gan Dywysog Cymru"
William and his wife, the Princess of Wales, were in the country earlier this week as the royal couple headed to Pontypridd, which was recently hit by Storms Bert and Daragh.
Their first visit was to Pontypridd Market, which has been at the heart of the community since 1805, where the duo went head-to-head as they tried their hand at making a batch of traditional Welsh cakes – and the future king thanked TV cook Mary Berry for his baking success.
With flour stuck to the sleeve of his maroon sweater, William smiled and joked: "Well, I don’t know [about] my stunning baking skills, Mary Berry taught me everything I need to know."
During their trip, the pair both sported yellow daffodil pins – the national flower of Wales, which is often worn on St David's Day. St David is the patron saint of the nation, a Welsh Christian prelate who served as Bishop of Mynyw during the sixth century.
Kate announced she was in remission from cancer in January, and the day trip is the latest in a run of appearances since the start of the year, which included a visit to a mother and baby unit in a women's prison in Cheshire recently.