Buckingham Palace is staging a display of a number of items detailing royal links with Poland for the country's president, Aleksander Kwasniewski.
The Queen Mother made numerous visits to people caught up in the war
Among the items is a 1941 letter from the Queen Mother describing a group of Polish soldiers as "very nice".
Mr Kwasniewski begins a three day state visit to the UK on Wednesday, just days after his country joined the European Union along with nine other countries.
Also on display are two 64-year-old dolls presented to the Queen in 1940.
Meeting in 'rabbit hole'
The items that have gone on display for the state visit have been taken from the Royal Collection and the Royal Archives.
The Queen Mother's letter was written to her 14-year-old daughter Princess Elizabeth.
She and her husband King George VI had visited the Commander-in-Chief of the
Polish Armed Forces General Sikorski and his soldiers at Barry Links and Carnoustie, north-east Scotland.
After France fell to the Germans in 1940 the exiled Polish government fled to London, where it remained during the World War II.
In a letter dated 7 March, the Queen Mother said: "Yesterday we spent with the Poles. They were very nice and we walked along miles of coast which they are guarding.
"We were asked occasionally to go down what looked like a large rabbit hole
and how we did it I don't know! But we did and came out again very nearly doubled
The then exiled Polish President Wladyslaw Raczkiewicz gave the 14-year-old Princess Elizabeth and her sister Princess Margaret the two dolls as Christmas presents.
The exhibition will take place at Buckingham Palace
Dressed in Polish national wedding costumes, the male and female wooden carved figures are taller than the average doll - with the groom standing 66cm in height.
Lady Jane Roberts, from the Royal Collection, said: "The exhibition is
intended as a very special personal thing - the letters from the Queen Mother to
the Queen and dolls that were given to her.
"I think the Queen expects us to do something very special."
Other items on display range from Queen Victoria's 1891 journal - in which she describes Polish pianist Ignacy Jan Paderewski as "very pale" - to love letters from 1718 cementing links between the Royal Family and Poland.