It was a family affair at the world-renowned horticultural show as The Queen and The Duke of Edinburgh were joined by The Prince of Wales and Prince Harry as they toured the displays.
Fresh from his tour in Australia and New Zealand, Prince Harry was reunited with his father and grandmother at Chelsea, greeting each with a kiss on the cheek.
The family toured a garden created for Sentebale, a charity founded by The Prince which helps vulnerable children in the small southern African country of Lesotho.
The Queen said well done to Prince Harry, who took a keen interest in the garden’s design.
Philip Green, chairman of Sentebale, said: "Harry is very authentic. If he says something, it’s his judgment, it’s not spin. He said it was perfect. I said, ‘do you really mean it’s perfect?‘. He said ’Yes, I wouldn’t change a thing’.
“It is an extreme privilege for us to have three generations of the Royal Family in one garden – for a high-profile but relatively small charity.
“The Queen walked the length of the garden. She was very complimentary about the planting.”
Garden designer Matt Keightley said: “They genuinely seemed interested and fascinated in the details. It was amazing to have so many of the royals.”
He said Prince Harry had taken a keen interest in the project and explained the garden to his father and grandparents.
The garden is inspired by a children’s centre the charity is building in Lesotho, and the prince hopes that touches from the garden can be added to the design of the centre.
Mr Keightley said: "Harry has been intrigued about the correlation between the Chelsea garden and the children’s centre so he was explaining to them which details would be taken out to the children’s centre.
“Before they arrived The Prince was talking about the one Lesothian poppy which is flowering in the garden and joking about whether we should have offered it up for a button hole. I said there is only one so we couldn’t possibly.
“The Royal Family members were interested in how many of the plants are native to Lesotho. I said 20%.”
He said The Queen “really liked” the trail of footprints that weave their way through the garden, made from the footprint of a child in Lesotho.
The designer joked that he and Prince Harry were worried they might be marked down by the judges because a television crew had been filming in the garden and left dirty footprints. There was a dash to spruce up the garden before the judges arrived to inspect it.
He said: "I had scrubbed the paving down for about an hour and a half. I was trying to keep everyone off it and then out of the corner of my eye I looked up and saw people walking through.
“I screamed ‘No!’. I looked up and it was the judges – so I had screamed at them which was unfortunate. I think they found it quite funny.”
Harry took an extensive tour of the Chelsea Flower Show, stopping off at several gardens and exhibits to look at the flowers.
As he was shown around the garden created for his charity, he spent a few minutes having a guided tour and chatting about it.
A Basothu choir dressed in colourful traditional outfits sang for him as he left the garden.
Smiling, Prince Harry shook each of their hands and chatted to the choir as he left.
The garden features bright flowers of oranges and reds, plants native to the small African country, and a waterfall to echo the nation’s oases.
Harry said the garden was “fantastic” and “everything I could have wished for”.
“From all the sketches of what it would look like, this is exactly how I imagined it,” he said. “It’s kind of perfect. If my garden was big enough, I would try and move it into my garden.”
The Prince said parts of it were “exactly like Africa”.
“I’m aware lots of people haven’t been to Africa, let alone Lesotho.”