Queen Elizabeth II has welcomed U.S. President Donald J Trump to Buckingham Palace to inspect the royal guards.

The U.S. President and his wife, First Lady Melania Trump, were flown to the grounds of Buckingham Palace on Marine One, landing on the West Lawn, where they were met by Prince Charles.

They party was also honoured by two 41-gun salutes fired simultaneously in Green Park, by the King’s Troop Royal Horse Artillery, and at the Tower of London by the Honourable Artillery Company.

The President of the United States and Mrs Trump are welcomed by The Queen on the West Terrace of Buckingham Palace. #USStateVisit pic.twitter.com/jJjx7JhzB8 — The Royal Family (@RoyalFamily) June 3, 2019

JUST IN: Queen Elizabeth II welcomes Pres. Trump and first lady Melania Trump to Buckingham Palace at start of three-day state visit to the U.K. https://t.co/J2JIq7Sxfi pic.twitter.com/jWxRutSKQQ — ABC News (@ABC) June 3, 2019

The President then met the Queen on the terrace, the pair shaking hands and exchanging a few words, with the monarch smiling broadly throughout the exchange.

This is not the first time President Trump met the Queen, having met her during his working visit in July 2018, joining her for tea at Windsor Castle. The Queen, then, appeared to enjoy the company of the President and that of the First Lady.

After greeting each other, the Queen joined Mr President and the First Lady to the terrace for the playing of the British and American anthems, before President Trump was escorted by Prince Charles and a Grenadier officer to inspect the guards assembled for the visit.

The red coated Brigade of Guards are known the world over for their stern role guarding Royal palaces and military buildings in London. While they typically remain silent while on duty, and stay unflinching when members of the public or tourists attempt to interact with them, if addressed by the commander in chief of the United States of America they would certainly have responded.

While the Guards are probably best known to the global public for their ceremonial duties in London, this is actually only a small part of their role as front-line combat troops. Guards have deployed alongside U.S. soldiers in Afghanistan and Iraq, where they were among the heaviest fighting. Grenadier Guard Lance Corporal James Ashworth was awarded a posthumous Victoria Cross, the highest British military decoration for valour in the face of the enemy, for his action in Helmand Province Afghanistan in 2012.

After the inspection, the Trumps and Royal Family returned to the interior of Buckingham Palace for a private lunch with the Queen.

Later in the day, the President will take a tour of Westminster Abbey and then meet with Prince Charles and Camilla, the Duchess of Cornwall, for tea at Clarence House, and in the evening there will be a State Banquet at Buckingham Palace.

The President and The Prince of Wales inspect a Guard of Honour formed by Nijmegen Company, Grenadier Guards. #USStateVisit pic.twitter.com/RwxRdLhm77 — The Royal Family (@RoyalFamily) June 3, 2019

Oliver JJ Lane contributed to this report.