During his speech at Buckingham Palace on Monday night, President Trump remembered D-Day and commended Queen Elizabeth II for her service during World War II. The anniversary of the largest war invasion in history is coming up on June 6, and while many Americans have been taught about WWII, few were likely aware of the British monarch's military service during it.

The queen is a trained a mechanic and worked for the Women's Auxiliary Territorial Service during the war, according the BBC. She learned how to fix machinery and drive a military truck.

Picture taken on 1945 at London showing Princess Elizabeth, the future Queen Elizabeth II. Getty

As Mr. Trump said during his state banquet speech, during the Blitz of 1940 and 1941, the Nazi war machine dropped thousands of bombs on Britain, many of them on London. Buckingham Palace was bombed 16 separate times during the war.

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The queen – then Princess Elizabeth – became an honorary second subaltern of the Army in 1945. The London Gazette announced the princess' service number in the Auxiliary Territorial Service; 23087.

A photo captured in April 1945 depicts the princess showing her mother, Queen Elizabeth I, a car engine that she worked on. Mr. Trump referenced that photo during his speech. "That young mechanic was the future Queen -- that great, great woman," he said. "Her Majesty inspired her compatriots in that fight to support the troops, defend their homeland, and defeat the enemy at all cost."

U.S. President Donald Trump, his wife First Lady Melania, Britain's Queen Elizabeth, Britain's Charles, the Prince of Wales and Camilla, Duchess of Cornwall pose at the State Banquet at Buckingham Palace in London, Britain June 3, 2019. Jeff Gilbert/Pool via REUTERS

Queen Elizabeth II is the only female member of the royal family to ever serve in the armed forces, according to the BBC, but her male descendants have followed – including Prince Harry, who served in the British Army for 10 years, officially leaving in 2015.

President Trump will travel to Portsmouth, England, and Normandy in France this week to commemorate the anniversary of the D-Day landing 75 years ago, when the queen was just 18 years old.