The Duchess of Cornwall stood out from the crowd in a psychedelic monochrome dress featuring eye-catching swirls and a flared hemline, accessorising with a simple pair of tan heels and styling her platinum locks in her trademark bouncy blow dry.
WATCH Camilla feed a horse in the garden of Clarence House!
Camilla, a keen equestrian enthusiast like the rest of the royal family, looked at ease as she greeted Splash, a 10-year-old Cob horse, and confidently fed him treats to the delight of onlookers.
Laura Boland, Ebony Horse Club's yard manager and chief instructor, praised the Duchess for her skill with Splash.
"Straight away, she was into Splash, asking was he OK. She had treats for him," Ms Boland told Town and Country magazine.
"She's lovely, and it was nice to have a common bond with somebody who is so invested in Ebony and invested in horses," she added.
Camilla made a short speech in which she praised Club staff and participants, saying: "Here it is now, going from strength to strength. The only thing is, we now need an Ebony Horse Club in every major city!"
The 71-year-old Duchess has been the President of Ebony Horse Club since 2009.
The organisation, based in Brixton, south London, is a community riding centre which helps children learn new skills and responsibilities through care for horses.
The reception comes after a busy week for Camilla, who started the month with a five-day tour of Wales with Prince Charles to mark the 50th anniversary of his investiture as Prince of Wales.
On Saturday, the Duchess attended the private ceremony for Prince Harry and Meghan Markle's son Archie's christening at Windsor Castle, along with Prince William, Kate Middleton and Princess Diana's sisters Lady Jane Fellowes and Lady Sarah McCorquodale.