Duchess Catherine wore a £49,000 golden necklace to the National Portrait Gallery yesterday (19.07.12).
The royal wore the piece - made up of a series of chains linked to five diamond-studded hoops - as she viewed the Olympic photography exhibition, The Road To 2012: Aiming High, which she viewed.
The piece, from the jeweller's Trinity range, has reportedly been part of her private collection for some time.
A St James's Palace spokesman said: "It's a personal piece which she's had for some time. It's not an official Olympic item but it's appropriate to wear it."
The duchess teamed the necklace with a blue crepe dress by Stella McCartney - who has also designed the British Olympic kits - and black Prada heels.
She viewed a selection of photographs including one of herself taken by Jillian Edlestein at a Team GB hockey event at the Olympic Park earlier this year.
Later at the exhibition, the duchess - who until her wedding was known as Kate Middleton - met Diana Gould, 100, the London 2012 Olympic torch relay's oldest female bearer.
Born in 1912, centenarian Diana runs exercise classes three times a week in the retirement flats where she lives. She will be will a torchbearer in the London Borough of Barnet as part of the 70-day relay.