Prince William shares a sweet throwback photo with Princess Diana and Prince Harry

And it’s to mark a day of celebration and appreciation for a group of incredible people.

September 9th is 999 Day or Emergency Services Day in the UK, a day to celebrate and say thank you to the police, fire and emergency medical services and specialised emergency services who work to keep the UK safe.
To mark the day Kensington Palace shared a sweet throwback photo from 1988 on Instagram, which featured Prince William and Prince Harry with their mother Princess Diana, and their two older cousins Peter Phillips and Zara Tindall, playing on a fire truck.
William and Harry were photographed wearing matching light blue coats and firefighter helmets while their eldest cousin Peter played driver, sitting behind the wheel of the vintage red truck.
"The first photograph in this post," the Instagram caption shares, "is of The Duke of Cambridge and The Duke of Sussex and their mother Diana, Princess of Wales, with their cousins Peter Phillips and Zara Tindall in the yard of the Old Fire Station 🚒 in the grounds of Sandringham House in 1988."

The palace shared the photo ahead of Prince William's visit to The Firefighter's Charity at Harcombe House in Devon, who offer specialised, lifelong support to members of the UK fire services community, empowering individual to achieve mental, physical and social wellbeing throughout their lives.
Speaking of the extraordinary work of the emergency services Prince William said: "As a society, we owe our wellbeing, and indeed our lives, to the men and women in our emergency services who work tirelessly to protect us in some of the most difficult circumstances.
"It is only fitting that we should recognise that vital role they play and pay tribute to the bravery and dedication of those who have made the ultimate sacrifice for their communities."

During his visit to Harcombe House The Duke visited the gym to see an anti-gravity treadmill in action, which allows those with lower limb injuries to exercise freely without putting their full weight on their feet, and met families undertaking an art therapy session.
William also met with families who have been support by Harcombe House, hearing about their experiences, the challenges they've faced and the impact of the support they've received at the centre.
The visit also marked the launch of a new partnership between Shout UK, a 24/7 text helpline which connects people in need with trained volunteers who provide help at a time when it is most needed, and the emergency services blue light community, to provide a 24/7 crisis text support to frontline emergency services communities, retired or serving, and their families across the UK.
"The conversation will flow by texting back and forth, sharing only what is comfortable," Kensington Palace explains.
"The Crisis Volunteer will listen without judgement, get them through the moment, help articulate the issue, and empower them to take the next steps."
Prince William with Shout UK volunteers. (Image: Instagram/@KensingtonRoyal)
Shout UK was launched by the Cambridges and the Sussexes in May – a free text messaging helpline for those experiencing mental health challenges to find a safe space to seek help and support – as an extension of Heads Together campaign.
In July, two months since its launch, Shout UK shared they had taken 100,000 text conversations equating to around 4 million messages of support.
999 Day begins annually at 9am on September 9th and is held to pay tribute to the invaluable work that is carried out by the emergency services and responders.