London (CNN) -- Exactly one year before Queen Elizabeth II celebrates 60 years on the throne, Buckingham Palace has announced plans of how the monarch's milestone will be celebrated.
The Diamond Jubilee will be marked with a special four-day holiday weekend in the UK -- from June 2 to 5, 2012 -- packed with enough pomp and spectacle to rival Prince William and Catherine Middleton's royal wedding.
Queen Elizabeth II ascended the throne on February 6, 1952 on the death of her father George VI. To become Britain's longest serving monarch, she will have to beat the record held by her great-great-grandmother, Queen Victoria and reign till September 10, 2015.
To kick off the celebrations on June 2, the Queen -- an expert equestrian - will attend the prestigious Epsom Derby horse race, which has been staged since 1780.
On June 3, London will play host to the largest flotilla assembled on the Thames in modern times. Up to 1,000 boats, ships and steamers from across the world will sail down the river in a 7.5 mile procession led by the Queen's Royal Barge.
Organizers expect up to a million people to line the river's banks to catch a glimpse of the water-borne parade, from its start in Putney, west London, to its finish at Tower Bridge.
"This is a wonderful way of expressing the country's gratitude and to celebrate [Queen Elizabeth's] reign," said a spokeswoman for the Pageant.
"Before Victorian times, the river was very regularly used for celebrations. This is where you'll have a piece of theatre on the water, with lots of boats, bands and performances that the country will come out to watch," she explained.
"We wanted to reference history - because this is a historical moment - but modernize as well, with boats from modern to historic, large to small, and motor or people powered."
The last time London saw anything on a similar scale was in 1622, when a flotilla followed King James I and his queen on their journey from Hampton Court, on the edge of London, to Whitehall, an event dubbed the "most magnificent triumph to ever be floated on the Thames."
Across the UK, people will participate in an ambitious street party picnic, called the Big Jubilee Lunch, which encourages people to share lunch with neighbors and friends -- with the aim of ending social isolation.
On June 4, a Diamond Jubilee Concert will be held at Buckingham Palace. At the concert's climax, a network of 2,012 Beacons will be lit across the Commonwealth and throughout Britain.
"The beacons will be lit by time zones, first in the Commonwealth countries, then in locations furthest away from the capital," organizer Bruno Peek told CNN. "With the last beacon -- the National Beacon -- lit by the Queen outside of Buckingham Palace."
To wrap up the celebrations, the Queen will attend a Service of Thanksgiving at St. Paul's Cathedral in London on Tuesday June 5.
Further details on the celebrations will be announced early in 2012. The UK government has already launched a dedicated Diamond Jubilee website providing regularly updated information related to the event.