This year symbolises the Platinum Jubilee of Britain's Queen Elizabeth II, marking the 70th anniversary of her reign as Queen of the United Kingdom and its 14 Commonwealth nations.
According to Buckingham Palace, after experiencing some discomfort during a military parade on Thursday, Queen Elizabeth will no longer attend Friday's Thanksgiving Service for her seven decades as monarch.
She appeared earlier on Thursday on the balcony of Buckingham Palace, waving at thousands of well-wishers.
Palace issued a statement:
"The Queen greatly enjoyed today’s Birthday Parade and Flypast but did experience some discomfort, taking into account the journey and activity required to participate in tomorrow’s National Service of Thanksgiving at St Paul’s Cathedral, Her Majesty with great reluctance has concluded that she will not attend."
The Platinum Jubilee marks the 70th anniversary of the reign of a British monarch, and Queen Elizabeth II is the first to reach this milestone. On significant anniversaries such as this one, commemorative events are held throughout the United Kingdom and Commonwealth countries.
After her father, King George VI, died on February 6, 1952, Elizabeth II became queen. The Queen usually spends the anniversary of her father's death at her Sandringham estate in quiet reflection, but this year she invited local community groups for a small celebration and viewed some Jubilee memorabilia.
Since Elizabeth's formal coronation occurred on June 2, 1953, Platinum Jubilee celebrations will begin on Thursday, June 2, and will last through the weekend.
Queen Elizabeth's Platinum Jubilee celebration: Details explored
To commemorate this historic anniversary, events will be held throughout the year. A four-day UK bank holiday weekend from Thursday, June 2nd to Sunday, June 5th, will also be observed. Public events, community activities, and national moments of reflection on The Queen's 70 years of service will be part of the four-day celebration too.
"Trooping the Color" will take place in central London on Thursday. In the 1700s, the traditional military ceremony became an annual event to commemorate the official birthday of the British sovereign.
The ceremony features a massive parade featuring over 1,400 soldiers and 400 musicians, as well as members of the royal family, in carriages and on horseback.
Ed Sheeran and Diana Ross will be among the celebrities performing at a live performance in the Queen's Honour on Saturday evening.
Thousands of people across the country arranged street celebrations on Sunday, with official support, and a large picnic lunch is also scheduled in Windsor, west London, as the Queen's primary residence is Windsor Castle.
The Duke and Duchess of Sussex, Prince Harry, and Meghan Markle, stated in May that they will be returning to the UK to celebrate the Platinum Jubilee. Archie and Lilibet, their two children, will accompany them. However, it was unclear which events they would attend.
Harry and Meghan are no longer "working members" of the royal family following a public feud with relatives a few years ago, and hence did not participate in official public tasks.