She added: "I think they really are a great example of how we can nurture our youth of today for a better tomorrow."
The Duchess of York's appearance at the event comes after she shed the pounds and showed off her new image in Hello! magazine earlier this year. The flame-haired mother of Princesses Beatrice and Eugenie said she was spurred into fitness action when she reached the same weight she was when pregnant with Bea.
She told the mag her weight gain "really frightened" her. "Beatrice was an 8lb baby and I was only 6lb off my full-blown pregnancy weight. I decided to make a change.
"I used to be so angry. I believed I was never going to lose the weight. I was just drowning in food," she went on.
"It took courage to go out in public in all the years I have been overweight.
"Every time there was a 'Duchess of Pork' or 'Fat Fergie' headline, they didn't have any idea they were reaching to the depths of my soul."
LOVE FERGIE? See more from the former royal in her style file below.