Britain’s longest serving monarch died on September 8, at Balmoral Castle, and has been lying in State for the past four days.
Hundreds of thousands of mourners queued for hours to say a final farewell in recent days.
Among the mourners will be Taoiseach Micheál Martin and President Michael D Higgins.
Here is everything your need to know about today’s Royal funeral.
The lying in State process ended at 6.30am this morning.
Before the funeral service, the tenor bell is tolled every minute for 96 minutes, reflecting the years of Queen Elizabeth II’s life. Members of foreign Royal families, heads of state, and overseas government representatives are received at the Great West Door by the Dean and Chapter of Westminster and are conducted to their seats in the Lantern. All remain seated.
The funeral service will be held at the historic Westminster Abbey from 11am. The service is expected to conclude by midday.
The ‘Last Post’ bugle ceremony will mark the end of the service and it will be followed by a two-minute national silence.
Following the funeral service, Queen Elizabeth’s coffin will be taken by procession to Wellington Arch, at Hyde Park Corner. The King and members of the Royal family will lead the procession.
The coffin will then be taken by hearse to Windsor Castle and from there another procession will take place to St George's Chapel in Windsor. The journey to Windsor is expected to take over two hours.
At 4pm the Royal family will attend a committal service at St George's chapel, which will end with the coffin being lowered into a vault.
Later this evening, at a private service, Queen Elizabeth will be interred at King George VI’s memorial chapel, inside St George's Chapel. The Queen will be laid to rest alongside her husband Prince Philip, who died last year.
President Michael D. Higgins, and Taoiseach Micheál Martin paid their respects at the catafalque of Britain’s Queen Elizabeth in Westminster Hall in London.
Mr Higgins and Mr Martin, along with their wives Sabina and Mary, attended the lying-in-state of the Queen. Also present was Martin Fraser, the Irish ambassador to Britain.
The funeral service will be aired on RTÉ One television, as well as the RTÉ News channel and RTÉ player from 10.30am until 12.30pm today.
The service will also be aired on BBC One from 8am today.
There will be 2,000 foreign dignitaries and guests will attend the funeral, ranging from King Charles III and other royals to world leaders including US President Joe Biden.
There will be 800 guests at a committal service later in the day at St George’s Chapel in Windsor Castle..
At least 1,650 military personnel will be involved in the procession of the queen’s coffin from Westminster Abbey to Wellington Arch after her funeral. A further 1,000 will line the streets along the procession route when the coffin reaches Windsor, 410 military personnel will take part in the procession, 480 will line streets, 150 will be in a guard of honour and line steps and 130 more will fulfil other ceremonial duties.
10,000 police officers are being deployed in the UK capital today. Metropolitan Police Deputy Assistant Commissioner Stuart Cundy said the “hugely complex” policing operation is the biggest in the London force’s history, surpassing the London 2012 Olympics which saw up to 10,000 police officers on duty per day.
22 miles (36 kilometers) of barriers have been erected in central London alone to control crowds and keep key areas around the Houses of Parliament, Westminster Abbey and Buckingham Palace secure.
London transport authorities expect 1 million people to flood into the capital today.
Additional reporting by AP News.