President Trump and King Charles are now reviewing the troops gathered at the White House, after performances by the U.S. Marine Band of "God Save the King" and "The Star-Spangled Banner."

King Charles and Queen Camilla have arrived at the South Portico of the White House for a formal state arrival ceremony. They are being greeted by President Donald Trump and first lady Melania Trump.

Notable officials are gathered on the White House South Lawn in rainy weather for the ceremony that will include a review of the troops, remarks by Trump and more.

President Trump is hosting King Charles III and Queen Camilla at the White House as the "special relationship" between the United States and the United Kingdom is under a microscope amid the war with Iran.

While Trump has repeatedly praised King Charles as a "friend" whom he's known for years, his relationship with U.K. Prime Minister Keir Starmer has been another story. The president has repeatedly assailed the U.K. and other NATO allies over the U.S. and Israeli war with Iran.

Trump said the visit from the king -- the U.K.'s constitutional and ceremonial head of state -- may help restore any damaged ties between the two allies.

"Absolutely. He's fantastic. He's a fantastic man. Absolutely the answer is yes," Trump told the BBC in a phone interview when asked if the visit could help repair the relationship.

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-ABC News' Nicholas Kerr

President Donald Trump and first lady Melania Trump will welcome Great Britain’s King Charles III and Queen Camilla to the White House South Lawn later this morning.

Thousands of guests are anticipated to be in attendance, including Cabinet officials, U.S. and U.K. delegations, members of Congress, students from the British International School of Washington and more.

The official arrival of the king and queen will begin with a traditional military arrival ceremony by the U.S. Army Herald Trumpets, a "tradition that dates back to the 18th century," the first lady’s office said. The national anthems of both countries will then be played by the U.S. Marine Band, followed by the Presidential Salute Battery rendering a 21-gun cannon salute.

"Following an Inspection of the Troops and a Troop in Review, facilitated by the U.S. Army Fife and Drum Corps, the President will deliver remarks from the South Lawn," the first lady's office said in a press release.

-ABC News' Emily Chang

Charles and Camilla’s first stop in New York City Wednesday was the National 9/11 Memorial, where they met with families of Sept. 11, 2001, victims and first responders.

The royals were greeted by former New York City mayor Michael Bloomberg, who showed them the memorial and stood by their side as they laid a bouquet of flowers.

The flowers were accompanied by a note that read, “We honour the memory of all those who so tragically lost their lives on 11th September 2001, and stand in enduring solidarity with the American people in the face of such profound loss. Charles R Camilla R," according to reporters who are traveling with the king and queen.

Other elected officials in attendance at the memorial were New York City Mayor Zohran Mamdani, New York Gov. Kathy Hochul and New Jersey Gov. Mikie Sherrill.