The young Prince, who was six at the time, was sadly pipped to the post by his classmates as they took part in a sack race at Wetherby School.
But his mother rushed in to save the day, as Diana ditched her shoes to take part in the school’s Mothers’ Race.
WATCH: Princess Diana saves the day at Prince Harry’s sports day
Wearing a black camisole with a matching blazer and a midi-length belted pleated skirt, Diana gave it her all as she sprinted off the starting block.
The royal mum-of-two looked all set to be triumphant in her efforts, but came a very close second as she crossed the finishing line.
But there were no hard feelings as Diana and her fellow school mums couldn’t stop giggling after the race.
Princess Diana sprinted to the finishing line
It wasn’t the first time the Princess had participated in the Mothers’ Race at William and Harry’s pre-preparatory school, having competed previously in 1989 and 1990.
The royal brothers attended Wetherby School in London before joining Ludgrove School near Wokingham, Berkshire, and then Eton College.
Prince Harry competing in the sack race
Princess Diana was tragically killed in a car crash in Paris in 1997 when William and Harry were aged just 15 and 12 respectively.
The pair were reunited on 1 July to unveil a statue of their late mother in the gardens at Kensington Palace.
In a joint statement, William and Harry said: “Today, on what would have been our mother’s 60th birthday, we remember her love, strength and character – qualities that made her a force for good around the world, changing countless lives for the better.
“Every day, we wish she were still with us, and our hope is that this statue will be seen forever as a symbol of her life and her legacy.
“Thank you to Ian Rank-Broadley, Pip Morrison and their teams for their outstanding work, to the friends and donors who helped make this happen, and to all those around the world who keep our mother’s memory alive.”
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