Laws handing May power over Article 50 - the clause in the EU treaties that contain the divorce procedures for the bloc - are expected to be law on or around March 15.
This will allow her to meet her timetable of triggering Article 50 and starting the two years of official exit talks before the end of the month.
The Royal Family have long been seen as crucial levers of "soft power" to the Government.
William travelled to Germany last summer, visiting Dusseldorf for a series of events honouring the role of British armed forces based in the country.
During a gala event, where the Duke gave a speech alongside Chancellor Angela Merkel, William claimed the "depth" of Britain's friendship with Germany would not change after Brexit.
The British monarchy has close ties with the European country, as a succession of sovereigns from George I, born in what is now modern Germany and who acceded to the throne in 1714, to William IV, who died in 1830, were also rulers of Hanover in Germany.
The 300th anniversary of what is known as the 'personal union' was celebrated in 2014, and the year before the milestone, princesses Beatrice and Eugenie visited Germany to highlight the event.
During a state visit to Germany in 2015, the Queen and Duke of Edinburgh visited the Bergen-Belsen concentration camp to mark the 70th anniversary of its liberation by British forces.
Kate has yet to make an official trip to Germany and the Cambridges have not toured Poland before on behalf of the Government.
Kensington Palace said full details of the visit would be released at a later date.
