The Prince and Princess of Wales recorded a special programme with BBC Radio 1's Newsbeat on Monday ahead of World Mental Health Day.
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The youth-focused news programme invited the royal couple to lead a discussion with campaigners and experts in the field of mental health.
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During a pre-recorded segment of Newsbeat, the royal couple shared details of their plans to take over the radio on Tuesday at 12.45pm. "Newsbeat will sound slightly different," teased Princess Kate.
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Prince William added: "As part of World Mental Health Day, Catherine and I have recorded a special programme, taking over the radio to talk about the importance of mental health."
© Photo: BBCThe royal couple made a surprise announcement
In a snippet from the extra special programme, the father-of-three said: "A toolbox is quite a useful analogy to use. A lot of people don't realise what they need until it comes along.
"You can be living one life one minute and something massively changes, and you realise you don't necessarily have the tools or the experience to be able to tackle that."
Touching on the variety of coping mechanisms, Kate added: "There's no right or wrong, different things will work for different people."
© Photo: BBCWilliam and Kate's special programme will air on Tuesday
Head of BBC Radio 1, Aled Haydn Jones, said: "It's been fantastic to welcome The Prince and Princess of Wales back to our studios to discuss something that is so close to both their and our audience's hearts.
"What was discussed today will resonate with so many of our listeners and it means so much to us that we can all work together to help tackle the stigma around this issue."
The royal couple's surprise announcement comes after the duo visited Northern Ireland for a day-long tour last week. Throughout the day, Prince William and Kate carried out a number of engagements with a selection of cross-community organisations offering support to people from varying backgrounds.
© Photo: Getty ImagesThe Prince and Princess of Wales visited Northern Ireland
In one sweet moment, the royal couple took part in a spirited cocktail-making race at an outdoor market in Belfast city centre. The next-in-line-to-the-throne and his wife laughed during the duel to be the quickest to make the potent drink before William was declared the winner.
Fans were delighted by the wholesome clip and were quick to pen their predictions online. "Love the fun but competitive nature," one said, while another wrote: "The Princess, naturally!" A third added: "Catherine," adding a string of blue love heart emojis and a fourth noted: "Catherine! Great video. Drinks look delicious!"
