Among Zara’s collection of sparkling accessories was a 5.52ct Magnifique white ring by Australian diamond specialist and Diamond Guild Australia member Calleija, which cost $550,000.

Princess Anne’s daughter also wore elegant Cascade drop earrings worth $115,000 and a black-and-white diamond cuff valued at $23,900.

Zara, 33, completed her summery look with a sleeveless monochrome dress and black strappy heels.

The Queen’s granddaughter was joined at the event on Queensland’s Gold Coast by Australian stars including Home and Away actress Demi Harman, weather presenter Sarah Cumming and Miss Universe runner-up Rachael Finch.