The Duke and Duchess of Cambridge and Prince Harry share an extremely close bond, with the trio often seen at royal engagements side-by-side and sharing a laugh. We take a look back at some of their sweetest moments. In 2013, when Kate was pregnant with Prince George, the British royals channelled their inner wizards at the Harry Potter set at Warner Bros Studios in Leavesden, Hertfordshire. They were invited to take a wand each before they were shown a few 'spells'.
The British royals were the perfect companions when they attended the Diamond Jubilee Thames River Pageant in London in June 2012.
They all showed their support at the 2012 Olympics in London, cheering Team GB from the sidelines.
Prince Harry was seen joking around with sister-in-law Kate during the 2014 Trooping the Colour festivities.
Last year, the trio joined children from various charities they support at BAFTA in London's Piccadilly where they watched Shaun the Sheep: The Farmer's Llamas - Kate even tried her hand at welly wanging before the movie.
The Duchess of Cambridge, Prince William and Prince Harry were all smiles when they met Usain Bolt on the second day of the Commonwealth Games in Glasgow, in 2014.
In 2012, the young royals visited an academy school in south-east London to open a project, which was being supported by their charitable foundation, in recognition of London hosting the Olympics.
The royal trio made a dazzling joint appearance at the world premiere of the latest Bond film, Spectre, in October 2015. Kate looked ravishing in a light-blue Jenny Packham gown with a sheer back, while the princes were both suited and booted for the occasion.
The British royals were out in full force for the culmination of the Queen's 90th birthday celebrations, earlier this year. The Duke and Duchess of Cambridge and Prince Harry were among the senior royals who stepped out for the Patron's Lunch on The Mall. They left the palace by car and travelled to the top of the Mall before getting out to greet the crowds, shaking hands and chatting to delighted guests who had braved the rain especially for the occasion.
Prince Harry and the Duke and Duchess of Cambridge joined forces to launch a new mental health campaign on the first day of Mental Health Awareness Week, in May. The trio were promoting the "Heads Together" project in a bid to end stigma surrounding mental health.