Barack Obama, visiting Britain for the first time as US president, shared a nervousness of the “palaces and pomp” with wife Michelle.

“We shouldn’t have worried,” the Democrat wrote following the Duke of Edinburgh’s death at the age of 99 on Friday.

“The Queen and Prince Philip immediately put us at ease with their grace and generosity, turning a ceremonial occasion into something far more natural, even comfortable.

“Prince Philip in particular was kind and warm, with a sharp wit and unfailing good humour. It was our first introduction to the man behind the title, and in the years since, our admiration for him has only grown.”

The Obamas first met the Queen and Philip in 2009 and would go on to share a warm bond with them during subsequent visits, once staying at Buckingham Palace in 2011.

The duke even drove the couple from their helicopter after touching down at Windsor Castle in 2016.

“I have to say I have never been driven by a Duke of Edinburgh before and I can report that it was very smooth riding,” Mr Obama said at the time.

Taken as a sign of their friendly relationship by some and as a breach of protocol by others, Ms Obama was pictured with her arm around the Queen during the first visit, a gesture the monarch returned.

Mr Obama, in the Facebook post on Friday, noted that “as two Americans unaccustomed to palaces and pomp, we didn’t know what to expect”.

But he highlighted Philip’s good nature in putting them at ease, adding: “We will miss him dearly.”

“At the Queen’s side or trailing the customary two steps behind, Prince Philip showed the world what it meant to be a supportive husband to a powerful woman,” he said.

“Yet he also found a way to lead without demanding the spotlight — serving in combat in World War II, commanding a frigate in the Royal Navy, and tirelessly touring the world to champion British industry and excellence. Through his extraordinary example, he proved that true partnership has room for both ambition and selflessness — all in service of something greater.

“As the world mourns his loss, we send our warmest wishes and deepest sympathies to the Queen, their children, grandchildren, and great-grandchildren; and everyone who knew and loved this remarkable man.”