U.S. President Donald Trump and his wife Melania were greeted by Queen Elizabeth II at Buckingham Palace on Monday.

The couple arrived at the palace by helicopter, landing in the Queen's back garden. Prince Charles and his wife, Camilla, welcomed the Trumps before they met the monarch.

Trump: 'Queen Elizabeth is a great, great woman'

Trump hailed Queen Elizabeth II as a "great, great woman" as the British monarch threw a lavish banquet for the U.S. president on Monday evening to kick off his three-day state visit.

Trump sat down to a glittering dinner with the British royal family in the Buckingham Palace ballroom as the UK rolled out the red carpet. Both Trump and the 93-year-old Queen praised the common bond between Britain and the United States.

"As we honor our shared victory and heritage, we affirm the common values that will unite us long into the future," Trump said at the banquet. "Freedom, sovereignty, self-determination, the rule of law and reverence for the rights given to us by almighty God."

He said Queen Elizabeth was "a constant symbol of these priceless traditions who embodied British dignity, duty and patriotism."

Queen Elizabeth said Britain and the United States had built post-war international institutions for "nations working together to safeguard a hard-won peace." The monarch said the two nations were united by their security, shared heritage, strong cultural links and strong economic ties. "I am confident that our common values and shared interests will continue to unite us."

Trump wades into UK's Brexit crisis as he arrives for the state visit

Trump arrived in Britain on Monday for a state visit, with his interventions on Brexit, outgoing Prime Minister Theresa May's successor and a row over China's Huawei set to overshadow the pomp and a banquet with Queen Elizabeth II.

Trump and Melania will be treated to a full display of British royal pageantry during the June 3-5 visit: lunch and a formal dinner with Queen Elizabeth II, tea with heir Prince Charles, and a tour of Westminster Abbey, coronation church of English monarchs for 1,000 years.

Beyond the ceremony, though, the proudly unpredictable 45th U.S. president also brings demands: he has praised a more radical Brexit-supporting potential successor to May and his envoys have urged a tougher British stance toward Chinese telecoms giant Huawei.

"I look forward to being a great friend to the United Kingdom, and am looking very much forward to my visit," Trump wrote on Twitter minutes before Air Force One landed.

Trump calls London mayor 'stone cold loser'

Shortly before the landing, the president also renewed his verbal attacks on London Mayor Sadiq Khan, calling him a "stone-cold loser" after the mayor criticized the British government's decision to offer a state visit to Trump.

"@SadiqKhan, who by all accounts has done a terrible job as Mayor of London, has been foolishly 'nasty' to the visiting President of the United States, by far the most important ally of the United Kingdom," Trump said on Twitter.

"He is a stone-cold loser who should focus on crime in London, not me."

Before he set off he repeated his message that there was an opportunity for a "very big trade deal" between the two countries in the near future.

Britain's so-called special relationship with the United States is an enduring alliance, but some British voters see Trump as crude, volatile and opposed to their values on issues ranging from global warming to his treatment of women.