King Charles III made a surprise appearance at the Royal Windsor Horse Show on Friday, greeting niece Zara Tindall with a sweet hug.

Charles was all smiles at the event, despite the pouring rain. It’s his third public-facing engagement in four days since his return to royal duties this week. His revamped schedule has been lightened while he undergoes treatment for an unspecified form of cancer, a diagnosis he shared in early February.

The Royal Windsor Horse Show was a favorite event of Charles’s late mother, Queen Elizabeth, and one that she made frequent appearances at in her life. Zara, daughter of Charles’s sister Princess Anne, is a former Olympic equestrian for Britain, and has spoken of the love of horses she shared with the late queen, calling the hobby their mutual “happy place.”

“I remember being around horses a lot when we used to go and see her,” she said in an interview in December 2023 to mark a year since her grandmother’s death. “She rode; grandfather was also involved with the horses, whether it was polo or carriage driving. And if we did anything pony-wise she’d come and watch and be really supportive. She very much knew what was going on in my career as I was growing up. And it was very much her happy place being with the horses. You got to see her real passion and love for the horses and that side of her.”

Beyond happiness at seeing family during a period when several senior royals are facing health difficulties (Kate Middleton also has cancer, with husband Prince William saying this week that she is “doing well,” and Sarah Ferguson is undergoing treatment for skin cancer, just a year after battling breast cancer), this specific event is a special one for both Tindall and Charles, with echoes of their departed grandmother and mother, respectively.

It’s been a busy week for the monarch. On Tuesday, with Queen Camilla by his side, the king visited with fellow cancer patients at the Macmillan Cancer Centre at University College Hospital in central London, sharing that he’s “not too bad” before heading off to his own treatment appointment.

Other royal attendees at the horse show Friday included Prince Edward and his wife Sophie, as well as Princess Anne and Vice Admiral Sir Timothy Laurence.