The Duchess wore the jewellery for a public appearance at the Royal College of Obstetricians and Gynaecologists in London.
She accessorised with the tanzanite pendant necklace by G. Collins and Sons, worth £8,400.
The added matching earrings that come with the set, designed to perfectly match her engagement ring.
Kate is very fond of Princess Diana’s jewellery, and also has a pair of Princess Diana’s diamond earrings, which she had restyled in a drop style.
However, this set appears to be much more modern, and the pair-shape is slightly different from Kate’s oval ring.
Much like Diana, Kate is very keen on wearing matching jewellery sets – a trend that has gone out of fashion with the general public.
Princess Diana was also a devotee to wearing stunning sets of matching jewels, clearly a taste she would have shared with her daughter-in-law.
Diana loved her huge sapphire choker, a gift from the Queen Mother, which was originally a brooch.
The last time Kate wore this set was at a Service of Commemoration and Drumhead Service on Horse Guards Parade in central London, in March last year.
She also wore the set in March 2015, at a Service of Commemoration to mark the end of combat operations in Afghanistan at St Paul’s Cathedral.
Kate Middleton and Meghan Markle appeared together today, both wearing blue.
Meghan’s sleeveless dress featured large lapels and epaulettes on the shoulders. A belt cinched in her waist, showing off her tiny frame.
When is Kate Middleton due?
The 36-year-old mother of two has been proudly displaying her baby bump during recent public appearances.
Royal fans will no doubt be looking forward to another little member of the Cambridge family.
What do we know about Kate Middleton’s pregnancy thus far?