The Prince of Wales and Duchess of Cornwall begin a four-day tour of America today which will see them meet US president Barack Obama.
Charles and Camilla are making their third joint official visit to America and will spend much of their time in the capital Washington highlighting a range of issues and celebrating historic milestones.
Mr Obama will sit down for informal talks with Charles and Camilla in his famous Oval office on Thursday and will be joined by his vice president Joe Biden.
The prince last met the president in May 2011, a few days after the royal wedding of the Duke and Duchess of Cambridge when the world leader confessed the glittering occasion had left America mesmerised.
Highlights of the trip include a tour of Mount Vernon - home of America's first president George Washington - and Charles will receive an award for exceptional leadership in conservation from the International Conservation Caucus Foundation.
The visit will see the royal couple mark major milestones, from the 150th anniversary of the end of the American civil war and death of president Abraham Lincoln, to the 800th anniversary of the Magna Carta.
Charles and Camilla will also visit the home city of renowned boxer Muhammad Ali.
Ali was born in Louisville, Kentucky and the royal couple will tour the city which features a cultural centre dedicated to the life and achievements of the three-time former heavyweight boxing champion.
Clarence House said: "Their Royal Highnesses will undertake a broad range of engagements to promote the UK's partnership with the United States in key areas such as sustainability and climate change, creating youth opportunities, encouraging corporate social responsibility and promoting historical and cultural links."
The royal couple will arrive later today and attend a reception at the British Ambassador's residence.
Tomorrow they will mark the 800th anniversary of Magna Carta during a visit to the National Archives where he will view the "Charters of Freedom" and the 1297 version of the Magna Carta, which is embodied in the American Bill of Rights and the Constitution.
He will also give a speech to representatives of major companies, leading environmental organisations and government - including Global Ocean Commission co-chairman David Miliband - gathered together to look at the issue of plastic waste in seas and oceans.
Meanwhile Camilla will visit the Shakespeare Theatre Company where she will tour the theatre, meet staff and children who use the theatre and then view a short production by the company's Text Alive programme.