Events take place in northern France to remember the largest seaborn invasion in history
D-Day veterans are joined by Theresa May, Emmanuel Macron, Donald Trump and Justin Trudeau
The day began with the sound of bagpipes marking the exact moment Allied troops landed 75 years ago
Prime Minister May and President Macron attend a ceremony for a new memorial in Ver-sur-Mer
A service is held at Bayeux Cathedral, at which veterans and church figures give readings
President Macron and President Trump pay tribute to US forces in a service at Colleville-sur-Mer
Canadian PM Justin Trudeau speaks at a ceremony at Juno Beach, where many Canadian forces landed
A service of remembrance is held in Arromanches, where wreaths are laid by veterans
In a break with tradition, President Trump and the First Lady won't be staying at Buckingham Palace because of on-going renovations.
Instead they will be staying at the US ambassador's residence Winfield House, in central London's Regent's Park.
Both former presidents George W Bush and Barack Obama were accommodated at Buckingham Palace during their respective state visits.
The US President will receive a ceremonial welcome attended by the Queen, Prince of Wales and Duchess of Cornwall in the Buckingham Palace garden.
After the welcome, the Duke of Sussex will join the group for a private lunch at the palace.
Mr and Mrs Trump will then visit Westminster Abbey for a tour with the Duke of York.
They will also meet Prince Charles and the Duchess of Cornwall for tea at Clarence House.
On Monday evening, a state banquet in the palace's ballroom will take place with Mr Trump, the Queen, Prince Charles and the Duchess of Cornwall joined by the Duke and Duchess of Cambridge, along with other UK public figures and prominent Americans living in Britain.
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Image source, ReutersFirst Lady as she boarded UK-bound Air Force One
Image source, ReutersThe First Lady stepping off Air Force One
Image source, PA
Image source, Getty ImagesForeign Secretary Jeremy Hunt was one of the first to greet the president when he stepped off the plane a few minutes ago.
Mr Trump has said Mr Hunt is one of the candidates for the Conservative party leadership he views most favourably.
President Trump and First Lady were greeted by US ambassador Woody Johnson and Foreign Secretary Jeremy Hunt.
Trump called Sadiq Khan a "stone cold loser".
In a tweet, Donald Trump called Sadiq Khan a "stone cold loser" and accused him of being "nasty".
It comes after Sadiq Khan said the UK should not be "rolling out the red carpet" for Donald Trump during the trip.
Mr Khan said he believed the prime minister should tell the president he was "wrong on a whole host of issues" such as his views on women and immigration.
But their feud isn't new. It first began in 2016 when Mr Trump challenged Mr Khan to an IQ test after Mr Khan said his views on Islam were "ignorant".
President Trump arrives at Stansted airport with First Lady Melania Trump to begin their three-day official state visit.
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The first lady prepared for her trip in style
Melania Trump's walked across the lawn of the White House in a Gucci dress covered with London landmarks, such as the Big Ben and Parliament, before she boarded Air Force One.
Image source, ReutersEtiquette expert Diana Mather tells BBC Radio 5 Live there are some things that visiting dignitaries cannot do when meeting the Queen:
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It's a formal trip to the UK by a head of state and is normally at the invitation of the Queen, who acts on advice from the government.
Although they're grand occasions, they're not just ceremonial affairs - they're also used by the government to further what it sees as Britain's national interests.
The Queen usually receives one or two heads of state per year and has hosted 112 of these visits since becoming monarch in 1952.
Mr Trump will only be the third US president to make a state visit to the UK, but the Queen has met almost all the US presidents in office during that time, either in the UK or in the US.
Towards the end of last week, people in London spotting aircraft flying over the capital - prompting some newspaper articles, external to explain that they were US military aircraft practising for President Trump's visit.
And this morning, one journalist from AFP tweeted that he'd seen helicopters over south London.
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The Essex airport tweets...
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US Marine Corps Sikorsky helicopters on the tarmac at Stansted
Air Force One - the specially-converted Boeing 747 airliner which is used to transport the US president around the world - is due to break the flow of Ryanairs and Easyjets at Stansted Airport when it lands at 09:00 BST. Pictures from the Essex airport show the first US military helicopters arriving ready to take the president and his entourage into central London.
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Maggie Haberman of the New York Times says Mr Trump is "very happy he was invited" for a state visit but there are "no real goals".
She says the president, his staff and family are more excited about meeting the Royal Family than almost any other aspect of the trip.
However, according to Haberman, a lot of White House officials have expressed trepidation and concern about why Mr Trump is bothering to have so many meetings with Prime Minister Theresa May, when her leadership is ending soon.