The Queen's funeral on Monday is set to be one of the biggest gatherings of royalty and politicians hosted in the UK for decades.
Invitations went out over the weekend, with some 500 heads of state and foreign dignitaries expected to attend.
The majority of leaders have been asked to arrive on commercial flights and told they will be bussed en masse from a site in west London.
The ceremony at Westminster Abbey has a capacity for around 2,200 people.
Here's what we know so far about who will and won't be in attendance.
European royal families
Members of royal families from across Europe, many of whom were blood relatives of the Queen, are expected.
Belgium's King Philippe and Queen Mathilde have confirmed they will be there, as have King Willem-Alexander of the Netherlands and his wife, Queen Maxima, along with his mother, former Dutch queen Princess Beatrix.
King Felipe and Queen Letizia of Spain have also accepted an invitation, as have the royal families of Norway, Sweden, Denmark and Monaco.
Leaders from across the Commonwealth, of which the Queen served as head for the entirety of her reign, are expected to attend.
Australian Prime Minister Anthony Albanese has accepted an invitation, as have New Zealand Prime Minister Jacinda Ardern and Canadian Prime Minister Justin Trudeau.
A number of governors-general who serve as the representative of the monarch in a Commonwealth realm are expected to attend with their countries' leaders.
Long-serving Bangladeshi Prime Minister Sheikh Hasina and Sri Lankan President Ranil Wickremesinghe have also reportedly accepted invitations. India will be represented by President Droupadi Murmu.
Other world leaders
Other world leaders said to have accepted invitations include Irish Taoiseach Micheal Martin, German President Frank-Walter Steinmeier, and Italian President Sergio Mattarella as well European Commission President Ursula von der Leyen.
South Korean President Yoon Suk-Yeol and Brazilian President Jair Bolsonaro have also confirmed their attendance.
Also expected to make the trip are Japanese Emperor Naruhito, Turkish President Recep Tayyip Erdoğan, and French President Emmanuel Macron.
It is not known whether Chinese President Xi Jinping, whose visits to Kazakhstan and Uzbekistan this week will mark the first time he has left China since the start of the Covid-19 pandemic, will receive an invite or would accept it.
The Islamic Republic of Iran, long the subject of international sanctions over its nuclear programme, will be represented only at ambassadorial level, Whitehall sources said.
Representatives from Syria, Venezuela and Afghanistan have not been invited, UK Government sources have told the BBC's James Landale.
This is because the UK does not have full diplomatic relations with these countries.
And North Korea (DPRK) and Nicaragua have been invited to send only ambassadors, not heads of state.
No-one from Russia, Belarus and Myanmar has been invited either.
Diplomatic relations between the UK and Russia have all but collapsed since Russia's invasion of Ukraine, and a spokesperson for Russian President Vladimir Putin said he was "not considering" attending the funeral.
The invasion was launched partially from the territory of Belarus, whose president, Aleksandr Lukashenko, is a close ally of President Putin's.
The UK has also significantly scaled back its diplomatic presence in Myanmar since a military coup in the country in February 2021.