Queen Elizabeth's funeral will take place tomorrow - the 10th day of mourning, 24NewsHD TV channel reported.
King Charles hosted the ceremony in honour of the visiting heads of state on the 10th day of mourning.
State heads including American President Joe Biden, Prime Minister Shehbaz Sharif, and Canadian Prime Minister Justin Trudeau are participating in the ceremony.
In view of security, the entrance of the public around Buckingham Palace was closed.
Those already present were removed from the park and walkways of Buckingham Palace.
The coffin of the late Queen Elizabeth remained in Westminster Hall on Sunday - the last day of the late Queen's public appearance.
Limited persons have been invited to the ceremony
Due to security reasons, public access to the area around Buckingham Palace is closed and people already present have been removed from the park and paths of Buckingham Palace.