Prince Harry and his wife Meghan have joined Prince William and wife Kate to look at the tributes and flowers left outside Windsor Castle following the death of Queen Elizabeth, with the two couples later greeting well-wishers.

Relations have been strained between the two sons of the King after Harry and Meghan moved to the United States and the four had not been seen so closely together since.

William’s spokesman said he had invited Harry and Meghan, officially known as the Duke and Duchess of Sussex, to join him and Kate as they examined the flowers and spoke to crowds lining the entrance to Windsor Castle.

The sight of the two couples together will raise hopes that there has been a rapprochement following the death of the United Kingdom’s longest-reigning monarch.

William was heard telling one well-wisher that the days following the Queen’s death had been “so surreal”.

“We all thought she was invincible,” he said.

The couples were dressed all in black as they walked along the gates of the castle.

A crowd at the castle broke out into applause as the couples approached members of the public and spoke to them.

William was seen speaking intently to a member of the crowd, at one moment shaking a woman’s hand. 

Both William and Kate, given the titles Prince and Princess of Wales, could be seen thanking people.

Kate crouched down at one moment and began speaking to a child who had started to cry. 

The child stopped crying when Kate approached her.

Meghan was also seen shaking the hands of several children and well-wishers at Windsor.

Harry and Meghan were handed bunches of flowers by the crowd which they both accepted.

William and Kate were also given bunches of flowers by members of the crowd as one visitor waved a Welsh flag in the background.

At one moment, a small Paddington Bear was given to William, which he passed on to an aide.

He was seen lightly touching Kate’s back at one moment as she crouched down to speak to a child at the front of the gates.

The crowd was heard chatting excitedly and taking photographs as William and Kate and the Duke and Duchess of Sussex stopped to speak to each person at the front of the barriers.

The royal couples walked along separately from one another, with William and Kate speaking to people on one side of the road and Harry and Meghan speaking to people on the other side of the road.

with PA