It followed the moment the Scotsman scored the triumph of his career, beating Roger Federer in the men's singles final to take gold.
He declared the victory "the biggest win of my life," adding: "I’ll never forget this moment."
The little boy, Master Caplain, had run down through the stands to the barriers of Centre Court, where he shouted: "Give me a hug" while reaching out to Andy.
Andy, who has become the first British man to win the gold in singles since Josiah Ritchie in 1908, replied: "Anything for a fan."
He then embraced the lad, who promptly burst into tears.
Andy then ran back onto the grass to celebrate his win, stopping for kisses and hugs with his delighted girlfriend Kim Sears and mum Judy.
Andy's win capped a stellar weekend for British Olympians, who are currently third in the medal table.
The 25-year-old added silver to the tally on Sunday after coming second in the mixed doubles with Laura Robson.
A day earlier there was another career high – this time for Greg Rutherford, when he won Britain's first long jump gold since 1964.
The crowd almost missed his glorious moment though, as they cheered Jessica Ennis to victory in the heptathlon.
The determined Olympian's single minded ability to focus on her goals and needs has been her key to success, according to those who know her.
This, she puts down to her passion for organising things. The 26-year-old has described herself as "a control freak" when it comes to packing her bags.
Jessica relaxes between competitions by planning her wedding to fiancé Andy Hill – it has been put off till next year so it won't interfere with the Olympics.
Of course, the Sheffield lass is blessed with natural talent, as the coach who discovered her will bear witness.
Marc Thompson, 53, saw her compete in the hurdles at a summer camp when she was ten. He was so impressed, especially when he found out it was her first go.
"She just glided over everything with a lot of speed. We thought she must have been coached in some way," he remembers.
"But when we asked her she said she had never done any hurdling before."
Also in the arena on what has been dubbed 'Super Saturday, was Mo Farah who sprinted to victory in a thrilling 10,000 metre final and sailor Ben Ainsley also won gold.
Elsewhere, the rowing team celebrated two more golds and a silver. Andrew Triggs Hodge, Pete Reed, Tom James and Alex Gregory beat Australia in the coxless fours, while Sophie Hosking and Katherine won the lightweight women's double scull.
Zac Purchase and Mark Hunter, the lightweight men's double scull champions in 2008, were narrowly beaten to the gold by Denmark.
There was a further silver and bronze in the gymnastics, with Louis Smith just missing out on the gold by a tenth of a point, and Max Whitlock joining him on the podium.
It's a little princess!