Kate, 35, wore her most fashion-forward outfit yet for the event, choosing a white dress with abstract pleats.
The dress came down in a deep V on the neckline, and the Duchess wore a black leaf belt around her waist.
Each of the pleats had their own individual cut-out pattern on them which was edged in black.
Kate kept the look sleek rather than edgy by pairing the dress with large pearls.
She wore a drop pearl necklace and large round pearl earrings, as well as carrying a simple black clutch.
The Duchess also kept her shoes simple, opting for plain black heels which buckled around the ankle.
Taking inspiration from the 60s, Kate wore her hair up in an elegant low bun, and chose to wear dark smoky eye makeup with a feline flick eyeliner.
White has been the theme so far for Kate’s wardrobe in Poland, as she arrived wearing a striking white suit.
Kate wore a smart white skirt-suit showing off her toned pins in a pair of nude tights; the mother-of-two carried her daughter off the plane.
The royals are in Poland and Germany from July 17 to 21.
A Kensington Palace spokesman said: “The Duke and Duchess are very much looking forward to this tour and are delighted with the exciting and varied programme that has been put together for it.
“They have decided that their children, Prince George and Princess Charlotte, will travel with them and we expect the children to be seen on at least a couple of occasions over the course of the week.”
In Poland, they will tour the former Stutthof concentration camp where 65,000 people died at the hands of their captors, and also visit Berlin’s Holocaust museum and memorial.
Chancellor Angela Merkel will hold a private meeting with the royal couple in Berlin at the start of the German leg of their tour on Wednesday.
After that the Duke and Duchess will visit the Brandenburg Gate, a symbol of German unification.
It has been a busy couple of weeks for Kate, who entertained the Spanish royals last week as well as attending the reveal of the new whale…