The Duchess of Cambridge revealed her sprinting ability and punching power when she put on a sporting display with some of Britain's best future athletic hopes.
Kate burst out of the blocks as she went up against former Olympic heptathlon champion Dame Jessica Ennis-Hill and two promising para-athletes - then asked for a re-run.
And she left Olympic gold medal hopeful Lutalo Muhammad joking about her "mean right hand" after the taekwondo competitor showed the duchess how to throw a punch.
Kate's sporting display came when she met young athletes and their parents at the London Stadium at the Olympic Park, for an event staged by SportsAid, a national charity helping the next generation of Olympic, Paralympic and Commonwealth champions.
Among the guests were past stars who have benefited from SportsAid support - double Olympic gold medal- winning swimmer Rebecca Adlington and former world heavyweight boxing champion David Haye.
Sprinter and para-athlete Emmanuel Oyinbo-Coker, an 18-year-old A-level student, showed the duchess how to mark out her starting blocks and, before their sprint start, she joked: "No pressure!"
Kate and husband William are known to have a competitive streak, and after the first attempt at a sprint start the foursome lined up again and travelled further along the indoor track at the stadium.
Oyinbo-Coker said afterwards: "She's not bad for a rookie", while his coach, Coral Nourice, added of Kate: "She was quite excited, that's why she wanted to have another go. I think she enjoyed it. You could see by her face, I don't think she fazed by it at all."
When Kate first arrived she was greeted by the sight of Muhammad putting some young hopefuls from his sport through their paces as they kicked pads he was holding.
The duchess, who wore a practical outfit of trainers, green trousers and a matching top, did not need to be asked twice when he offered to show her how to punch.
Kate asked about her technique and Muhammad replied: "Instructors will tell you 'Punch through your opponent, not round them'."
He added later: "She did well, actually, I must confess a lot better than expected. Her right hand is mean, I hope she never has to use it for self-defence but at least she's got some skills now."
The event celebrated the efforts of parents who support a young son or daughter in pursuit of sporting excellence.
Every year, SportsAid helps more than 1,000 athletes - the vast majority aged 12-18 - by providing a financial award to help with training and competition costs.
The Rio 2016 Games saw 150 medals won by Olympic and Paralympic competitors supported by the sporting charity.